diff --git a/changes/config-settings-search.md b/changes/config-settings-search.md
new file mode 100644
index 00000000..0300ec73
--- /dev/null
+++ b/changes/config-settings-search.md
@@ -0,0 +1,4 @@
+type: fixed
+area: config
+
+- Fixed Configuration window search so it searches across all categories, narrows on multi-word terms, hides settings owned by richer editors, and no longer shows the Open File button.
diff --git a/changes/note-fields-default-note-type.md b/changes/note-fields-default-note-type.md
new file mode 100644
index 00000000..6de3fe73
--- /dev/null
+++ b/changes/note-fields-default-note-type.md
@@ -0,0 +1,4 @@
+type: fixed
+area: config
+
+- Defaulted the note-fields note type picker to `Kiku` when available, then Lapis note types, otherwise leaving it blank for manual selection.
diff --git a/changes/subtitle-css-appearance-editor.md b/changes/subtitle-css-appearance-editor.md
new file mode 100644
index 00000000..cc4532ae
--- /dev/null
+++ b/changes/subtitle-css-appearance-editor.md
@@ -0,0 +1,4 @@
+type: changed
+area: config
+
+- Config: Primary and secondary subtitle appearance now use color controls plus CSS declaration editors, saved as `subtitleStyle.css` and `subtitleStyle.secondary.css`.
diff --git a/config.example.jsonc b/config.example.jsonc
index e998ca87..0cb0faa7 100644
--- a/config.example.jsonc
+++ b/config.example.jsonc
@@ -360,6 +360,7 @@
   // ==========================================
   "subtitleStyle": {
     "primaryDefaultMode": "visible", // Default primary subtitle bar visibility mode. hidden hides it, visible shows it, hover reveals it on hover. Values: hidden | visible | hover
+    "css": {}, // CSS declaration object applied to primary subtitles after normal subtitle style defaults.
     "enableJlpt": false, // Enable JLPT vocabulary level underlines. When disabled, JLPT tagging lookup and underlines are skipped. Values: true | false
     "preserveLineBreaks": false, // Preserve line breaks in visible overlay subtitle rendering. When false, line breaks are flattened to spaces for a single-line flow. Values: true | false
     "autoPauseVideoOnHover": true, // Automatically pause mpv playback while hovering subtitle text, then resume on leave. Values: true | false
@@ -406,6 +407,7 @@
       ] // Five colors used for rank bands when mode is `banded` (from most common to least within topX).
     }, // Frequency dictionary setting.
     "secondary": {
+      "css": {}, // CSS declaration object applied to secondary subtitles after normal subtitle style defaults.
       "fontFamily": "Inter, Noto Sans, Helvetica Neue, sans-serif", // Font family setting.
       "fontSize": 24, // Font size setting.
       "fontColor": "#cad3f5", // Font color setting.
@@ -523,6 +525,7 @@
       "autoUpdateNewCards": true // Automatically update newly added cards. Values: true | false
     }, // Behavior setting.
     "nPlusOne": {
+      "enabled": false, // Enable N+1 subtitle highlighting (highlights the one unknown word in a sentence). Requires known-word cache data. Values: true | false
       "minSentenceWords": 3 // Minimum sentence word count required for N+1 targeting (default: 3).
     }, // N plus one setting.
     "metadata": {
@@ -530,7 +533,7 @@
     }, // Metadata setting.
     "isLapis": {
       "enabled": false, // Enable Lapis-specific mining behaviors and sentence card model targeting. Values: true | false
-      "sentenceCardModel": "Japanese sentences" // Note type name used by Lapis sentence cards.
+      "sentenceCardModel": "Lapis" // Note type name used by Lapis sentence cards.
     }, // Is lapis setting.
     "isKiku": {
       "enabled": false, // Enable Kiku-specific mining behaviors (duplicate handling, field grouping). Values: true | false
diff --git a/docs-site/configuration.md b/docs-site/configuration.md
index ff2070bf..95dee4ee 100644
--- a/docs-site/configuration.md
+++ b/docs-site/configuration.md
@@ -324,25 +324,29 @@ See `config.example.jsonc` for detailed configuration options.
 ```json
 {
   "subtitleStyle": {
-    "fontFamily": "Hiragino Sans, M PLUS 1, Source Han Sans JP, Noto Sans CJK JP",
-    "fontSize": 35,
     "fontColor": "#cad3f5",
-    "fontWeight": "600",
-    "lineHeight": 1.35,
-    "letterSpacing": "-0.01em",
-    "wordSpacing": 0,
-    "fontKerning": "normal",
-    "textRendering": "geometricPrecision",
-    "textShadow": "0 2px 6px rgba(0,0,0,0.9), 0 0 12px rgba(0,0,0,0.55)",
-    "fontStyle": "normal",
     "backgroundColor": "transparent",
-    "backdropFilter": "blur(6px)",
+    "css": {
+      "font-family": "Hiragino Sans, M PLUS 1, Source Han Sans JP, Noto Sans CJK JP",
+      "font-size": "35px",
+      "font-weight": "600",
+      "line-height": "1.35",
+      "letter-spacing": "-0.01em",
+      "word-spacing": "0",
+      "font-kerning": "normal",
+      "text-rendering": "geometricPrecision",
+      "text-shadow": "0 2px 6px rgba(0,0,0,0.9), 0 0 12px rgba(0,0,0,0.55)",
+      "font-style": "normal",
+      "backdrop-filter": "blur(6px)"
+    },
     "secondary": {
-      "fontFamily": "Inter, Noto Sans, Helvetica Neue, sans-serif",
-      "fontSize": 24,
       "fontColor": "#cad3f5",
-      "textShadow": "0 2px 6px rgba(0,0,0,0.9), 0 0 12px rgba(0,0,0,0.55)",
-      "backgroundColor": "transparent"
+      "backgroundColor": "transparent",
+      "css": {
+        "font-family": "Inter, Noto Sans, Helvetica Neue, sans-serif",
+        "font-size": "24px",
+        "text-shadow": "0 2px 6px rgba(0,0,0,0.9), 0 0 12px rgba(0,0,0,0.55)"
+      }
     }
   }
 }
@@ -353,6 +357,7 @@ See `config.example.jsonc` for detailed configuration options.
 | `fontFamily`                       | string      | CSS font-family value (default: `"Hiragino Sans, M PLUS 1, Source Han Sans JP, Noto Sans CJK JP"`)                         |
 | `fontSize`                         | number (px) | Font size in pixels (default: `35`)                                                                                        |
 | `fontColor`                        | string      | Any CSS color value (default: `"#cad3f5"`)                                                                                 |
+| `css`                              | object      | CSS declarations applied to subtitles after normal style defaults; the settings window writes textbox edits here            |
 | `fontWeight`                       | string      | CSS font-weight, e.g. `"bold"`, `"normal"`, `"600"` (default: `"600"`)                                                     |
 | `fontStyle`                        | string      | `"normal"` or `"italic"` (default: `"normal"`)                                                                             |
 | `backgroundColor`                  | string      | Any CSS color, including `"transparent"` (default: `"transparent"`)                                                        |
@@ -374,7 +379,9 @@ See `config.example.jsonc` for detailed configuration options.
 | `frequencyDictionary.singleColor`  | string      | Color used for all highlighted tokens in single mode                                                                       |
 | `frequencyDictionary.bandedColors` | string[]    | Array of five hex colors used for ranked bands in banded mode                                                              |
 | `jlptColors`                       | object      | JLPT level underline colors object (`N1`..`N5`)                                                                            |
-| `secondary`                        | object      | Override any of the above for secondary subtitles (optional)                                                               |
+| `secondary`                        | object      | Override any of the above for secondary subtitles (optional), including `secondary.css` declarations                       |
+
+The configuration window keeps subtitle color controls separate, then saves the CSS textbox to `subtitleStyle.css` and `subtitleStyle.secondary.css`. Existing top-level style keys such as `fontSize` and `textShadow` remain supported for hand-written configs.
 
 Frequency dictionary highlighting uses the same dictionary file format as JLPT bundle lookups (`term_meta_bank_*.json` under discovered dictionary directories). A token is highlighted when it has a positive integer `frequencyRank` (lower is more common) and the rank is within `topX`.
 
@@ -967,6 +974,7 @@ This example is intentionally compact. The option table below documents availabl
 | `ankiConnect.knownWords.matchMode`                | `"headword"`, `"surface"`               | Matching strategy for known-word highlighting (default: `"headword"`). `headword` uses token headwords; `surface` uses visible subtitle text.                                                       |
 | `ankiConnect.knownWords.refreshMinutes`           | number                                  | Minutes between known-word cache refreshes (default: `1440`)                                                                                                                                        |
 | `ankiConnect.knownWords.decks`                    | object                                  | Deck→fields mapping used for known-word cache query scope (e.g. `{ "Kaishi 1.5k": ["Word", "Word Reading"] }`).                                                                                     |
+| `ankiConnect.nPlusOne.enabled`                    | `true`, `false`                         | Enable N+1 subtitle highlighting (highlights the one unknown word in a sentence). Independent from `knownWords.highlightEnabled`. Requires known-word cache data (default: `false`).               |
 | `ankiConnect.nPlusOne.minSentenceWords`           | number                                  | Minimum number of words required in a sentence before single unknown-word N+1 highlighting can trigger (default: `3`).                                                                              |
 | `behavior.notificationType`                       | `"osd"`, `"system"`, `"both"`, `"none"` | Notification type on card update (default: `"osd"`)                                                                                                                                                 |
 | `behavior.autoUpdateNewCards`                     | `true`, `false`                         | Automatically update cards on creation (default: `true`)                                                                                                                                            |
diff --git a/docs-site/public/config.example.jsonc b/docs-site/public/config.example.jsonc
index e998ca87..0cb0faa7 100644
--- a/docs-site/public/config.example.jsonc
+++ b/docs-site/public/config.example.jsonc
@@ -360,6 +360,7 @@
   // ==========================================
   "subtitleStyle": {
     "primaryDefaultMode": "visible", // Default primary subtitle bar visibility mode. hidden hides it, visible shows it, hover reveals it on hover. Values: hidden | visible | hover
+    "css": {}, // CSS declaration object applied to primary subtitles after normal subtitle style defaults.
     "enableJlpt": false, // Enable JLPT vocabulary level underlines. When disabled, JLPT tagging lookup and underlines are skipped. Values: true | false
     "preserveLineBreaks": false, // Preserve line breaks in visible overlay subtitle rendering. When false, line breaks are flattened to spaces for a single-line flow. Values: true | false
     "autoPauseVideoOnHover": true, // Automatically pause mpv playback while hovering subtitle text, then resume on leave. Values: true | false
@@ -406,6 +407,7 @@
       ] // Five colors used for rank bands when mode is `banded` (from most common to least within topX).
     }, // Frequency dictionary setting.
     "secondary": {
+      "css": {}, // CSS declaration object applied to secondary subtitles after normal subtitle style defaults.
       "fontFamily": "Inter, Noto Sans, Helvetica Neue, sans-serif", // Font family setting.
       "fontSize": 24, // Font size setting.
       "fontColor": "#cad3f5", // Font color setting.
@@ -523,6 +525,7 @@
       "autoUpdateNewCards": true // Automatically update newly added cards. Values: true | false
     }, // Behavior setting.
     "nPlusOne": {
+      "enabled": false, // Enable N+1 subtitle highlighting (highlights the one unknown word in a sentence). Requires known-word cache data. Values: true | false
       "minSentenceWords": 3 // Minimum sentence word count required for N+1 targeting (default: 3).
     }, // N plus one setting.
     "metadata": {
@@ -530,7 +533,7 @@
     }, // Metadata setting.
     "isLapis": {
       "enabled": false, // Enable Lapis-specific mining behaviors and sentence card model targeting. Values: true | false
-      "sentenceCardModel": "Japanese sentences" // Note type name used by Lapis sentence cards.
+      "sentenceCardModel": "Lapis" // Note type name used by Lapis sentence cards.
     }, // Is lapis setting.
     "isKiku": {
       "enabled": false, // Enable Kiku-specific mining behaviors (duplicate handling, field grouping). Values: true | false
diff --git a/package.json b/package.json
index 73add775..db5217b8 100644
--- a/package.json
+++ b/package.json
@@ -50,8 +50,8 @@
     "test:plugin:src": "lua scripts/test-plugin-lua-compat.lua && lua scripts/test-plugin-start-gate.lua && lua scripts/test-plugin-session-bindings.lua && lua scripts/test-plugin-binary-windows.lua",
     "test:launcher:smoke:src": "bun test launcher/smoke.e2e.test.ts",
     "test:launcher:src": "bun test launcher/config.test.ts launcher/config-domain-parsers.test.ts launcher/config/cli-parser-builder.test.ts launcher/config/args-normalizer.test.ts launcher/mpv.test.ts launcher/picker.test.ts launcher/parse-args.test.ts launcher/main.test.ts launcher/commands/command-modules.test.ts launcher/commands/update-command.test.ts launcher/smoke.e2e.test.ts && bun run test:plugin:src",
-    "test:core:src": "bun test src/preload-settings.test.ts src/cli/args.test.ts src/cli/help.test.ts src/shared/setup-state.test.ts src/core/services/cli-command.test.ts src/core/services/field-grouping-overlay.test.ts src/core/services/numeric-shortcut-session.test.ts src/core/services/secondary-subtitle.test.ts src/core/services/mpv-render-metrics.test.ts src/core/services/overlay-content-measurement.test.ts src/core/services/mpv-control.test.ts src/core/services/mpv.test.ts src/core/services/runtime-options-ipc.test.ts src/core/services/runtime-config.test.ts src/core/services/yomitan-extension-paths.test.ts src/core/services/yomitan-extension-loader.test.ts src/core/services/yomitan-settings.test.ts src/core/services/config-hot-reload.test.ts src/core/services/discord-presence.test.ts src/core/services/tokenizer.test.ts src/core/services/tokenizer/annotation-stage.test.ts src/core/services/tokenizer/parser-selection-stage.test.ts src/core/services/tokenizer/parser-enrichment-stage.test.ts src/core/services/subsync.test.ts src/core/services/overlay-bridge.test.ts src/core/services/overlay-shortcut-handler.test.ts src/core/services/stats-window.test.ts src/core/services/__tests__/stats-server.test.ts src/main/runtime/stats-server-routing.test.ts src/core/services/mining.test.ts src/core/services/anki-jimaku.test.ts src/core/services/jimaku-download-path.test.ts src/core/services/jellyfin.test.ts src/core/services/jellyfin-remote.test.ts src/core/services/immersion-tracker-service.test.ts src/core/services/overlay-runtime-init.test.ts src/core/services/app-ready.test.ts src/core/services/startup-bootstrap.test.ts src/core/services/subtitle-processing-controller.test.ts src/core/services/anilist/anilist-update-queue.test.ts src/core/services/anilist/rate-limiter.test.ts src/core/services/jlpt-token-filter.test.ts src/core/services/subtitle-position.test.ts src/core/utils/shortcut-config.test.ts src/main/runtime/startup-mode-flags.test.ts src/main/runtime/first-run-setup-plugin.test.ts src/main/runtime/first-run-setup-service.test.ts src/main/runtime/first-run-setup-window.test.ts src/main/runtime/command-line-launcher.test.ts src/main/runtime/tray-runtime.test.ts src/main/runtime/tray-main-actions.test.ts src/main/runtime/tray-main-deps.test.ts src/main/runtime/tray-runtime-handlers.test.ts src/main/runtime/cli-command-context-main-deps.test.ts src/main/runtime/app-ready-main-deps.test.ts src/main/runtime/update/appimage-updater.test.ts src/main/runtime/update/fetch-adapter.test.ts src/main/runtime/update/release-metadata-policy.test.ts src/main/runtime/update/update-dialogs.test.ts src/main/runtime/update/support-assets.test.ts src/renderer/error-recovery.test.ts src/renderer/subtitle-render.test.ts src/renderer/handlers/mouse.test.ts src/renderer/handlers/keyboard.test.ts src/renderer/modals/jimaku.test.ts src/subsync/utils.test.ts src/main/anilist-url-guard.test.ts src/window-trackers/hyprland-tracker.test.ts src/window-trackers/x11-tracker.test.ts src/window-trackers/windows-helper.test.ts src/window-trackers/windows-tracker.test.ts launcher/config.test.ts launcher/config-domain-parsers.test.ts launcher/config/cli-parser-builder.test.ts launcher/config/args-normalizer.test.ts launcher/parse-args.test.ts launcher/main.test.ts launcher/commands/command-modules.test.ts launcher/commands/update-command.test.ts launcher/setup-gate.test.ts stats/src/lib/api-client.test.ts stats/src/hooks/useExcludedWords.test.ts",
-    "test:core:dist": "bun test dist/cli/args.test.js dist/cli/help.test.js dist/core/services/cli-command.test.js dist/core/services/ipc.test.js dist/core/services/anki-jimaku-ipc.test.js dist/core/services/field-grouping-overlay.test.js dist/core/services/numeric-shortcut-session.test.js dist/core/services/secondary-subtitle.test.js dist/core/services/mpv-render-metrics.test.js dist/core/services/overlay-content-measurement.test.js dist/core/services/mpv-control.test.js dist/core/services/mpv.test.js dist/core/services/runtime-options-ipc.test.js dist/core/services/runtime-config.test.js dist/core/services/yomitan-extension-paths.test.js dist/core/services/config-hot-reload.test.js dist/core/services/discord-presence.test.js dist/core/services/tokenizer.test.js dist/core/services/tokenizer/annotation-stage.test.js dist/core/services/tokenizer/parser-selection-stage.test.js dist/core/services/tokenizer/parser-enrichment-stage.test.js dist/core/services/subsync.test.js dist/core/services/overlay-bridge.test.js dist/core/services/overlay-manager.test.js dist/core/services/overlay-shortcut-handler.test.js dist/core/services/mining.test.js dist/core/services/anki-jimaku.test.js dist/core/services/jimaku-download-path.test.js dist/core/services/jellyfin.test.js dist/core/services/jellyfin-remote.test.js dist/core/services/immersion-tracker-service.test.js dist/core/services/overlay-runtime-init.test.js dist/core/services/app-ready.test.js dist/core/services/startup-bootstrap.test.js dist/core/services/subtitle-processing-controller.test.js dist/core/services/anilist/anilist-token-store.test.js dist/core/services/anilist/anilist-update-queue.test.js dist/core/services/anilist/rate-limiter.test.js dist/core/services/jlpt-token-filter.test.js dist/core/services/subtitle-position.test.js dist/renderer/error-recovery.test.js dist/renderer/subtitle-render.test.js dist/renderer/handlers/mouse.test.js dist/renderer/handlers/keyboard.test.js dist/renderer/modals/jimaku.test.js dist/subsync/utils.test.js dist/main/anilist-url-guard.test.js dist/window-trackers/hyprland-tracker.test.js dist/window-trackers/x11-tracker.test.js dist/window-trackers/windows-helper.test.js dist/window-trackers/windows-tracker.test.js",
+    "test:core:src": "bun test src/preload-settings.test.ts src/settings/settings-anki-controls.test.ts src/cli/args.test.ts src/cli/help.test.ts src/shared/setup-state.test.ts src/core/services/cli-command.test.ts src/core/services/field-grouping-overlay.test.ts src/core/services/numeric-shortcut-session.test.ts src/core/services/secondary-subtitle.test.ts src/core/services/mpv-render-metrics.test.ts src/core/services/overlay-content-measurement.test.ts src/core/services/mpv-control.test.ts src/core/services/mpv.test.ts src/core/services/runtime-options-ipc.test.ts src/core/services/runtime-config.test.ts src/core/services/yomitan-extension-paths.test.ts src/core/services/yomitan-extension-loader.test.ts src/core/services/yomitan-settings.test.ts src/core/services/config-hot-reload.test.ts src/core/services/discord-presence.test.ts src/core/services/tokenizer.test.ts src/core/services/tokenizer/annotation-stage.test.ts src/core/services/tokenizer/parser-selection-stage.test.ts src/core/services/tokenizer/parser-enrichment-stage.test.ts src/core/services/subsync.test.ts src/core/services/overlay-bridge.test.ts src/core/services/overlay-shortcut-handler.test.ts src/core/services/stats-window.test.ts src/core/services/__tests__/stats-server.test.ts src/main/runtime/stats-server-routing.test.ts src/core/services/mining.test.ts src/core/services/anki-jimaku.test.ts src/core/services/jimaku-download-path.test.ts src/core/services/jellyfin.test.ts src/core/services/jellyfin-remote.test.ts src/core/services/immersion-tracker-service.test.ts src/core/services/overlay-runtime-init.test.ts src/core/services/app-ready.test.ts src/core/services/startup-bootstrap.test.ts src/core/services/subtitle-processing-controller.test.ts src/core/services/anilist/anilist-update-queue.test.ts src/core/services/anilist/rate-limiter.test.ts src/core/services/jlpt-token-filter.test.ts src/core/services/subtitle-position.test.ts src/core/utils/shortcut-config.test.ts src/main/runtime/startup-mode-flags.test.ts src/main/runtime/first-run-setup-plugin.test.ts src/main/runtime/first-run-setup-service.test.ts src/main/runtime/first-run-setup-window.test.ts src/main/runtime/command-line-launcher.test.ts src/main/runtime/tray-runtime.test.ts src/main/runtime/tray-main-actions.test.ts src/main/runtime/tray-main-deps.test.ts src/main/runtime/tray-runtime-handlers.test.ts src/main/runtime/cli-command-context-main-deps.test.ts src/main/runtime/app-ready-main-deps.test.ts src/main/runtime/update/appimage-updater.test.ts src/main/runtime/update/fetch-adapter.test.ts src/main/runtime/update/release-metadata-policy.test.ts src/main/runtime/update/update-dialogs.test.ts src/main/runtime/update/support-assets.test.ts src/renderer/error-recovery.test.ts src/renderer/subtitle-render.test.ts src/renderer/handlers/mouse.test.ts src/renderer/handlers/keyboard.test.ts src/renderer/modals/jimaku.test.ts src/subsync/utils.test.ts src/main/anilist-url-guard.test.ts src/window-trackers/hyprland-tracker.test.ts src/window-trackers/x11-tracker.test.ts src/window-trackers/windows-helper.test.ts src/window-trackers/windows-tracker.test.ts launcher/config.test.ts launcher/config-domain-parsers.test.ts launcher/config/cli-parser-builder.test.ts launcher/config/args-normalizer.test.ts launcher/parse-args.test.ts launcher/main.test.ts launcher/commands/command-modules.test.ts launcher/commands/update-command.test.ts launcher/setup-gate.test.ts stats/src/lib/api-client.test.ts stats/src/hooks/useExcludedWords.test.ts",
+    "test:core:dist": "bun test dist/settings/settings-anki-controls.test.js dist/cli/args.test.js dist/cli/help.test.js dist/core/services/cli-command.test.js dist/core/services/ipc.test.js dist/core/services/anki-jimaku-ipc.test.js dist/core/services/field-grouping-overlay.test.js dist/core/services/numeric-shortcut-session.test.js dist/core/services/secondary-subtitle.test.js dist/core/services/mpv-render-metrics.test.js dist/core/services/overlay-content-measurement.test.js dist/core/services/mpv-control.test.js dist/core/services/mpv.test.js dist/core/services/runtime-options-ipc.test.js dist/core/services/runtime-config.test.js dist/core/services/yomitan-extension-paths.test.js dist/core/services/config-hot-reload.test.js dist/core/services/discord-presence.test.js dist/core/services/tokenizer.test.js dist/core/services/tokenizer/annotation-stage.test.js dist/core/services/tokenizer/parser-selection-stage.test.js dist/core/services/tokenizer/parser-enrichment-stage.test.js dist/core/services/subsync.test.js dist/core/services/overlay-bridge.test.js dist/core/services/overlay-manager.test.js dist/core/services/overlay-shortcut-handler.test.js dist/core/services/mining.test.js dist/core/services/anki-jimaku.test.js dist/core/services/jimaku-download-path.test.js dist/core/services/jellyfin.test.js dist/core/services/jellyfin-remote.test.js dist/core/services/immersion-tracker-service.test.js dist/core/services/overlay-runtime-init.test.js dist/core/services/app-ready.test.js dist/core/services/startup-bootstrap.test.js dist/core/services/subtitle-processing-controller.test.js dist/core/services/anilist/anilist-token-store.test.js dist/core/services/anilist/anilist-update-queue.test.js dist/core/services/anilist/rate-limiter.test.js dist/core/services/jlpt-token-filter.test.js dist/core/services/subtitle-position.test.js dist/renderer/error-recovery.test.js dist/renderer/subtitle-render.test.js dist/renderer/handlers/mouse.test.js dist/renderer/handlers/keyboard.test.js dist/renderer/modals/jimaku.test.js dist/subsync/utils.test.js dist/main/anilist-url-guard.test.js dist/window-trackers/hyprland-tracker.test.js dist/window-trackers/x11-tracker.test.js dist/window-trackers/windows-helper.test.js dist/window-trackers/windows-tracker.test.js",
     "test:core:smoke:dist": "bun test dist/cli/help.test.js dist/core/services/runtime-config.test.js dist/core/services/ipc.test.js dist/core/services/overlay-manager.test.js dist/core/services/anilist/anilist-token-store.test.js dist/core/services/startup-bootstrap.test.js dist/renderer/error-recovery.test.js dist/main/anilist-url-guard.test.js dist/window-trackers/x11-tracker.test.js",
     "test:smoke:dist": "bun run test:config:smoke:dist && bun run test:core:smoke:dist",
     "test:subtitle:src": "bun test src/core/services/subsync.test.ts src/subsync/utils.test.ts",
diff --git a/src/anki-integration/known-word-cache.ts b/src/anki-integration/known-word-cache.ts
index 5bc72fd6..20221704 100644
--- a/src/anki-integration/known-word-cache.ts
+++ b/src/anki-integration/known-word-cache.ts
@@ -277,7 +277,8 @@ export class KnownWordCacheManager {
   }
 
   private isKnownWordCacheEnabled(): boolean {
-    return this.deps.getConfig().knownWords?.highlightEnabled === true;
+    const config = this.deps.getConfig();
+    return config.knownWords?.highlightEnabled === true || config.nPlusOne?.enabled === true;
   }
 
   private shouldAddMinedWordsImmediately(): boolean {
diff --git a/src/anki-integration/runtime.ts b/src/anki-integration/runtime.ts
index c1327b9a..4db953a2 100644
--- a/src/anki-integration/runtime.ts
+++ b/src/anki-integration/runtime.ts
@@ -157,7 +157,8 @@ export class AnkiIntegrationRuntime {
   }
 
   applyRuntimeConfigPatch(patch: Partial<AnkiConnectConfig>): void {
-    const wasKnownWordCacheEnabled = this.config.knownWords?.highlightEnabled === true;
+    const wasKnownWordCacheEnabled =
+      this.config.knownWords?.highlightEnabled === true || this.config.nPlusOne?.enabled === true;
     const previousKnownWordCacheConfig = wasKnownWordCacheEnabled
       ? this.getKnownWordCacheLifecycleConfig(this.config)
       : null;
@@ -207,7 +208,8 @@ export class AnkiIntegrationRuntime {
     };
     this.config = normalizeAnkiIntegrationConfig(mergedConfig);
     this.deps.onConfigChanged?.(this.config);
-    const nextKnownWordCacheEnabled = this.config.knownWords?.highlightEnabled === true;
+    const nextKnownWordCacheEnabled =
+      this.config.knownWords?.highlightEnabled === true || this.config.nPlusOne?.enabled === true;
 
     if (wasKnownWordCacheEnabled && !nextKnownWordCacheEnabled) {
       if (this.started) {
diff --git a/src/config/definitions/defaults-integrations.ts b/src/config/definitions/defaults-integrations.ts
index 9730d677..f878da77 100644
--- a/src/config/definitions/defaults-integrations.ts
+++ b/src/config/definitions/defaults-integrations.ts
@@ -69,6 +69,7 @@ export const INTEGRATIONS_DEFAULT_CONFIG: Pick<
       autoUpdateNewCards: true,
     },
     nPlusOne: {
+      enabled: false,
       minSentenceWords: 3,
     },
     metadata: {
@@ -76,7 +77,7 @@ export const INTEGRATIONS_DEFAULT_CONFIG: Pick<
     },
     isLapis: {
       enabled: false,
-      sentenceCardModel: 'Japanese sentences',
+      sentenceCardModel: 'Lapis',
     },
     isKiku: {
       enabled: false,
diff --git a/src/config/definitions/defaults-subtitle.ts b/src/config/definitions/defaults-subtitle.ts
index 028f1ae2..b3674e7c 100644
--- a/src/config/definitions/defaults-subtitle.ts
+++ b/src/config/definitions/defaults-subtitle.ts
@@ -3,6 +3,7 @@ import { ResolvedConfig } from '../../types/config';
 export const SUBTITLE_DEFAULT_CONFIG: Pick<ResolvedConfig, 'subtitleStyle' | 'subtitleSidebar'> = {
   subtitleStyle: {
     primaryDefaultMode: 'visible',
+    css: {},
     enableJlpt: false,
     preserveLineBreaks: false,
     autoPauseVideoOnHover: true,
@@ -43,6 +44,7 @@ export const SUBTITLE_DEFAULT_CONFIG: Pick<ResolvedConfig, 'subtitleStyle' | 'su
       bandedColors: ['#ed8796', '#f5a97f', '#f9e2af', '#8bd5ca', '#8aadf4'],
     },
     secondary: {
+      css: {},
       fontFamily: 'Inter, Noto Sans, Helvetica Neue, sans-serif',
       fontSize: 24,
       fontColor: '#cad3f5',
diff --git a/src/config/definitions/options-integrations.ts b/src/config/definitions/options-integrations.ts
index d6f3320b..0d15665f 100644
--- a/src/config/definitions/options-integrations.ts
+++ b/src/config/definitions/options-integrations.ts
@@ -278,6 +278,12 @@ export function buildIntegrationConfigOptionRegistry(
       defaultValue: defaultConfig.ankiConnect.knownWords.addMinedWordsImmediately,
       description: 'Immediately append newly mined card words into the known-word cache.',
     },
+    {
+      path: 'ankiConnect.nPlusOne.enabled',
+      kind: 'boolean',
+      defaultValue: defaultConfig.ankiConnect.nPlusOne.enabled,
+      description: 'Enable N+1 subtitle highlighting (highlights the one unknown word in a sentence). Requires known-word cache data.',
+    },
     {
       path: 'ankiConnect.nPlusOne.minSentenceWords',
       kind: 'number',
diff --git a/src/config/definitions/options-subtitle.ts b/src/config/definitions/options-subtitle.ts
index 8fd500a1..fc8cbd1b 100644
--- a/src/config/definitions/options-subtitle.ts
+++ b/src/config/definitions/options-subtitle.ts
@@ -13,6 +13,20 @@ export function buildSubtitleConfigOptionRegistry(
       description:
         'Default primary subtitle bar visibility mode. hidden hides it, visible shows it, hover reveals it on hover.',
     },
+    {
+      path: 'subtitleStyle.css',
+      kind: 'object',
+      defaultValue: defaultConfig.subtitleStyle.css,
+      description:
+        'CSS declaration object applied to primary subtitles after normal subtitle style defaults.',
+    },
+    {
+      path: 'subtitleStyle.secondary.css',
+      kind: 'object',
+      defaultValue: defaultConfig.subtitleStyle.secondary.css,
+      description:
+        'CSS declaration object applied to secondary subtitles after normal subtitle style defaults.',
+    },
     {
       path: 'subtitleStyle.enableJlpt',
       kind: 'boolean',
diff --git a/src/config/resolve/anki-connect.ts b/src/config/resolve/anki-connect.ts
index ee8549ab..fd263bac 100644
--- a/src/config/resolve/anki-connect.ts
+++ b/src/config/resolve/anki-connect.ts
@@ -789,6 +789,21 @@ export function applyAnkiConnectResolution(context: ResolveContext): void {
       DEFAULT_CONFIG.ankiConnect.knownWords.addMinedWordsImmediately;
   }
 
+  const nPlusOneEnabled = asBoolean(nPlusOneConfig.enabled);
+  if (nPlusOneEnabled !== undefined) {
+    context.resolved.ankiConnect.nPlusOne.enabled = nPlusOneEnabled;
+  } else if (nPlusOneConfig.enabled !== undefined) {
+    context.warn(
+      'ankiConnect.nPlusOne.enabled',
+      nPlusOneConfig.enabled,
+      context.resolved.ankiConnect.nPlusOne.enabled,
+      'Expected boolean.',
+    );
+    context.resolved.ankiConnect.nPlusOne.enabled = DEFAULT_CONFIG.ankiConnect.nPlusOne.enabled;
+  } else {
+    context.resolved.ankiConnect.nPlusOne.enabled = DEFAULT_CONFIG.ankiConnect.nPlusOne.enabled;
+  }
+
   const nPlusOneMinSentenceWords = asNumber(nPlusOneConfig.minSentenceWords);
   const hasValidNPlusOneMinSentenceWords =
     nPlusOneMinSentenceWords !== undefined &&
diff --git a/src/config/resolve/subtitle-domains.ts b/src/config/resolve/subtitle-domains.ts
index fdf80964..c95794be 100644
--- a/src/config/resolve/subtitle-domains.ts
+++ b/src/config/resolve/subtitle-domains.ts
@@ -10,6 +10,21 @@ import {
   isObject,
 } from './shared';
 
+function asCssDeclarations(value: unknown): Record<string, string> | undefined {
+  if (!isObject(value)) return undefined;
+
+  const declarations: Record<string, string> = {};
+  for (const [property, declarationValue] of Object.entries(value)) {
+    if (typeof declarationValue !== 'string') {
+      return undefined;
+    }
+    if (declarationValue.trim().length > 0) {
+      declarations[property] = declarationValue.trim();
+    }
+  }
+  return declarations;
+}
+
 export function applySubtitleDomainConfig(context: ResolveContext): void {
   const { src, resolved, warn } = context;
 
@@ -159,6 +174,8 @@ export function applySubtitleDomainConfig(context: ResolveContext): void {
     const fallbackSubtitleStyleNameMatchColor = resolved.subtitleStyle.nameMatchColor;
     const fallbackSubtitleStyleKnownWordColor = resolved.subtitleStyle.knownWordColor;
     const fallbackSubtitleStyleNPlusOneColor = resolved.subtitleStyle.nPlusOneColor;
+    const fallbackSubtitleStyleCss = { ...resolved.subtitleStyle.css };
+    const fallbackSubtitleStyleSecondaryCss = { ...resolved.subtitleStyle.secondary.css };
     const fallbackFrequencyDictionary = {
       ...resolved.subtitleStyle.frequencyDictionary,
     };
@@ -211,6 +228,35 @@ export function applySubtitleDomainConfig(context: ResolveContext): void {
       );
     }
 
+    const css = asCssDeclarations((src.subtitleStyle as { css?: unknown }).css);
+    if (css !== undefined) {
+      resolved.subtitleStyle.css = css;
+    } else if ((src.subtitleStyle as { css?: unknown }).css !== undefined) {
+      resolved.subtitleStyle.css = fallbackSubtitleStyleCss;
+      warn(
+        'subtitleStyle.css',
+        (src.subtitleStyle as { css?: unknown }).css,
+        resolved.subtitleStyle.css,
+        'Expected an object whose values are CSS declaration strings.',
+      );
+    }
+
+    const rawSecondary = isObject(src.subtitleStyle.secondary)
+      ? (src.subtitleStyle.secondary as { css?: unknown })
+      : undefined;
+    const secondaryCss = asCssDeclarations(rawSecondary?.css);
+    if (secondaryCss !== undefined) {
+      resolved.subtitleStyle.secondary.css = secondaryCss;
+    } else if (rawSecondary?.css !== undefined) {
+      resolved.subtitleStyle.secondary.css = fallbackSubtitleStyleSecondaryCss;
+      warn(
+        'subtitleStyle.secondary.css',
+        rawSecondary.css,
+        resolved.subtitleStyle.secondary.css,
+        'Expected an object whose values are CSS declaration strings.',
+      );
+    }
+
     const preserveLineBreaks = asBoolean(
       (src.subtitleStyle as { preserveLineBreaks?: unknown }).preserveLineBreaks,
     );
diff --git a/src/config/resolve/subtitle-style.test.ts b/src/config/resolve/subtitle-style.test.ts
index 37368ea8..3fde4003 100644
--- a/src/config/resolve/subtitle-style.test.ts
+++ b/src/config/resolve/subtitle-style.test.ts
@@ -28,6 +28,46 @@ test('subtitleStyle preserveLineBreaks falls back while merge is preserved', ()
   );
 });
 
+test('subtitleStyle css declarations accept string declaration maps and warn on invalid values', () => {
+  const valid = createResolveContext({
+    subtitleStyle: {
+      css: {
+        'font-size': '42px',
+        'text-wrap': 'balance',
+      },
+      secondary: {
+        css: {
+          'text-transform': 'uppercase',
+        },
+      },
+    },
+  });
+  applySubtitleDomainConfig(valid.context);
+  assert.deepEqual(valid.context.resolved.subtitleStyle.css, {
+    'font-size': '42px',
+    'text-wrap': 'balance',
+  });
+  assert.deepEqual(valid.context.resolved.subtitleStyle.secondary.css, {
+    'text-transform': 'uppercase',
+  });
+
+  const invalid = createResolveContext({
+    subtitleStyle: {
+      css: {
+        'font-size': 42,
+      } as never,
+      secondary: {
+        css: 'font-size: 28px;' as never,
+      },
+    },
+  });
+  applySubtitleDomainConfig(invalid.context);
+  assert.deepEqual(invalid.context.resolved.subtitleStyle.css, {});
+  assert.deepEqual(invalid.context.resolved.subtitleStyle.secondary.css, {});
+  assert.ok(invalid.warnings.some((warning) => warning.path === 'subtitleStyle.css'));
+  assert.ok(invalid.warnings.some((warning) => warning.path === 'subtitleStyle.secondary.css'));
+});
+
 test('subtitleStyle autoPauseVideoOnHover falls back on invalid value', () => {
   const { context, warnings } = createResolveContext({
     subtitleStyle: {
diff --git a/src/config/settings/jsonc-edit.ts b/src/config/settings/jsonc-edit.ts
index 08d91176..66851f69 100644
--- a/src/config/settings/jsonc-edit.ts
+++ b/src/config/settings/jsonc-edit.ts
@@ -188,7 +188,7 @@ export function buildConfigSettingsSnapshot(
       continue;
     }
 
-    values[field.configPath] = structuredClone(rawValue !== undefined ? rawValue : resolvedValue);
+    values[field.configPath] = structuredClone(rawValue != null ? rawValue : resolvedValue);
   }
 
   return {
diff --git a/src/config/settings/registry.test.ts b/src/config/settings/registry.test.ts
index 32b7cbdc..1d74b8a8 100644
--- a/src/config/settings/registry.test.ts
+++ b/src/config/settings/registry.test.ts
@@ -28,17 +28,60 @@ test('settings registry groups annotation display fields by config group', () =>
   assert.equal(field('subtitleStyle.jlptColors.N1').control, 'color');
 });
 
+test('settings registry routes known words sync, n+1, and frequency config to behavior', () => {
+  assert.equal(field('ankiConnect.knownWords.addMinedWordsImmediately').category, 'behavior');
+  assert.equal(field('ankiConnect.knownWords.addMinedWordsImmediately').section, 'Known Words');
+  assert.equal(field('ankiConnect.knownWords.decks').category, 'behavior');
+  assert.equal(field('ankiConnect.knownWords.decks').section, 'Known Words');
+  assert.equal(field('ankiConnect.knownWords.matchMode').category, 'behavior');
+  assert.equal(field('ankiConnect.knownWords.matchMode').section, 'Known Words');
+  assert.equal(field('ankiConnect.knownWords.refreshMinutes').category, 'behavior');
+  assert.equal(field('ankiConnect.knownWords.refreshMinutes').section, 'Known Words');
+  assert.equal(field('ankiConnect.nPlusOne.minSentenceWords').category, 'behavior');
+  assert.equal(field('ankiConnect.nPlusOne.minSentenceWords').section, 'N+1');
+  assert.equal(field('subtitleStyle.frequencyDictionary.sourcePath').category, 'behavior');
+  assert.equal(field('subtitleStyle.frequencyDictionary.sourcePath').section, 'Frequency Highlighting');
+  assert.equal(field('subtitleStyle.frequencyDictionary.mode').category, 'behavior');
+  assert.equal(field('subtitleStyle.frequencyDictionary.matchMode').category, 'behavior');
+  assert.equal(field('subtitleStyle.frequencyDictionary.topX').category, 'behavior');
+});
+
 test('settings registry exposes specialized controls for config-assisted inputs', () => {
   assert.equal(field('ankiConnect.knownWords.decks').control, 'known-words-decks');
   assert.equal(field('ankiConnect.isLapis.sentenceCardModel').control, 'anki-note-type');
   assert.equal(field('ankiConnect.fields.word').control, 'anki-field');
   assert.equal(field('keybindings').control, 'mpv-keybindings');
+  assert.equal(field('subtitleStyle.css').control, 'css-declarations');
+  assert.equal(field('subtitleStyle.secondary.css').control, 'css-declarations');
   assert.equal(field('shortcuts.copySubtitle').control, 'keyboard-shortcut');
-  assert.equal(field('subtitleSidebar.toggleKey').control, 'key-code');
   assert.equal(field('stats.toggleKey').control, 'key-code');
   assert.equal(field('discordPresence.presenceStyle').control, 'select');
 });
 
+test('settings registry exposes css declaration editor for primary and secondary subtitle appearance', () => {
+  const primaryVisible = fields
+    .filter(
+      (candidate) =>
+        candidate.section === 'Primary Subtitle Appearance' && !candidate.settingsHidden,
+    )
+    .map((candidate) => candidate.configPath);
+  const secondaryVisible = fields
+    .filter(
+      (candidate) =>
+        candidate.section === 'Secondary Subtitle Appearance' && !candidate.settingsHidden,
+    )
+    .map((candidate) => candidate.configPath);
+
+  assert.deepEqual(primaryVisible, ['subtitleStyle.css']);
+  assert.deepEqual(secondaryVisible, ['subtitleStyle.secondary.css']);
+  assert.equal(field('subtitleStyle.fontSize').settingsHidden, true);
+  assert.equal(field('subtitleStyle.secondary.fontSize').settingsHidden, true);
+  assert.equal(field('subtitleStyle.fontColor').settingsHidden, true);
+  assert.equal(field('subtitleStyle.backgroundColor').settingsHidden, true);
+  assert.equal(field('subtitleStyle.hoverTokenColor').settingsHidden, true);
+  assert.equal(field('subtitleStyle.hoverTokenBackgroundColor').settingsHidden, true);
+});
+
 test('settings registry puts feature toggles first, then other toggles alphabetically', () => {
   const ankiConnect = fields.filter((candidate) => candidate.section === 'AnkiConnect');
   assert.equal(ankiConnect[0]?.configPath, 'ankiConnect.enabled');
@@ -48,7 +91,7 @@ test('settings registry puts feature toggles first, then other toggles alphabeti
   );
 
   const kikuLapis = fields.filter(
-    (candidate) => candidate.section === 'Kiku Features And Lapis Features',
+    (candidate) => candidate.section === 'Kiku/Lapis Features',
   );
   assert.deepEqual(
     kikuLapis.slice(0, 2).map((candidate) => candidate.configPath),
@@ -68,6 +111,8 @@ test('settings registry hides app-managed and inactive config surfaces', () => {
     'jellyfin.defaultLibraryId',
     'jellyfin.deviceId',
     'jellyfin.clientName',
+    'subtitleSidebar.toggleKey',
+    'jellyfin.recentServers',
   ]) {
     assert.equal(paths.has(hiddenPath), false, `${hiddenPath} should be hidden`);
   }
diff --git a/src/config/settings/registry.ts b/src/config/settings/registry.ts
index 5f3ca3e5..53f227a9 100644
--- a/src/config/settings/registry.ts
+++ b/src/config/settings/registry.ts
@@ -6,6 +6,10 @@ import type {
   ConfigSettingsRestartBehavior,
 } from '../../types/settings';
 import { CONFIG_OPTION_REGISTRY, DEFAULT_CONFIG } from '../definitions';
+import {
+  getSubtitleCssManagedConfigPaths,
+  getSubtitleCssScopeForPath,
+} from '../../settings/subtitle-style-css';
 
 type Leaf = {
   path: string;
@@ -67,6 +71,8 @@ export const LEGACY_HIDDEN_CONFIG_PATHS = [
   'jellyfin.defaultLibraryId',
   'jellyfin.deviceId',
   'controller.buttonIndices',
+  'subtitleSidebar.toggleKey',
+  'jellyfin.recentServers',
 ] as const;
 
 const EXCLUDED_PREFIXES = ['controller.buttonIndices', 'youtubeSubgen'] as const;
@@ -76,11 +82,19 @@ const JSON_OBJECT_FIELDS = new Set([
   'controller.bindings',
   'controller.profiles',
   'ankiConnect.knownWords.decks',
+  'subtitleStyle.css',
+  'subtitleStyle.secondary.css',
 ]);
 
 const SECRET_PATHS = new Set(['ai.apiKey', 'jimaku.apiKey', 'anilist.accessToken']);
 
 const COLOR_SUFFIXES = new Set(['Color', 'color', 'backgroundColor', 'singleColor', 'nPlusOne']);
+const SUBTITLE_CSS_MANAGED_CONFIG_PATHS = new Set([
+  ...getSubtitleCssManagedConfigPaths('primary'),
+  ...getSubtitleCssManagedConfigPaths('secondary'),
+  'subtitleStyle.hoverTokenColor',
+  'subtitleStyle.hoverTokenBackgroundColor',
+]);
 
 const OPTION_BY_PATH = new Map(CONFIG_OPTION_REGISTRY.map((entry) => [entry.path, entry]));
 
@@ -106,7 +120,7 @@ const SECTION_ORDER = new Map<string, number>(
     'Subtitle Sidebar Behavior',
     'Note Fields',
     'Media Capture',
-    'Kiku Features And Lapis Features',
+    'Kiku/Lapis Features',
     'Anki AI',
     'AnkiConnect Proxy',
     'AnkiConnect',
@@ -123,20 +137,48 @@ const PATH_ORDER = new Map<string, number>(
     'ankiConnect.proxy.enabled',
     'ankiConnect.isLapis.enabled',
     'ankiConnect.isKiku.enabled',
+    'subtitleStyle.fontColor',
+    'subtitleStyle.backgroundColor',
+    'subtitleStyle.hoverTokenColor',
+    'subtitleStyle.hoverTokenBackgroundColor',
+    'subtitleStyle.css',
+    'subtitleStyle.secondary.fontColor',
+    'subtitleStyle.secondary.backgroundColor',
+    'subtitleStyle.secondary.css',
+    'secondarySub.defaultMode',
+    'secondarySub.secondarySubLanguages',
   ].map((path, index) => [path, index]),
 );
 
 const SUBSECTION_ORDER = new Map<string, number>(
-  ['Known Words', 'N+1', 'JLPT', 'Frequency Dictionary', 'Character Names'].map(
-    (subsection, index) => [subsection, index],
-  ),
+  [
+    'Known Words',
+    'N+1',
+    'JLPT',
+    'Frequency Highlighting',
+    'Character Names',
+    'Mining & Clipboard',
+    'Toggle & Visibility',
+    'Open Panels',
+    'Playback',
+    'Timing',
+    'Default Fold State',
+  ].map((subsection, index) => [subsection, index]),
 );
 
 const LABEL_OVERRIDES: Record<string, string> = {
+  'ankiConnect.knownWords.highlightEnabled': 'Enabled',
+  'ankiConnect.nPlusOne.enabled': 'Enabled',
+  'ankiConnect.isLapis.enabled': 'Enable Lapis Features',
+  'ankiConnect.isKiku.enabled': 'Enable Kiku Features',
+  'stats.toggleKey': 'Toggle Stats Overlay',
+  'shortcuts.openCharacterDictionary': 'Open AniList Override',
   'subtitleSidebar.pauseVideoOnHover': 'Pause Video On Hover - Sidebar',
   'subtitleStyle.autoPauseVideoOnHover': 'Pause Video On Hover - Subtitles',
   'subtitleStyle.autoPauseVideoOnYomitanPopup': 'Pause Video On Yomitan Popup',
   'subtitleStyle.primaryDefaultMode': 'Primary Subtitle Visibility Mode',
+  'subtitleStyle.css': 'CSS Declarations',
+  'subtitleStyle.secondary.css': 'CSS Declarations',
   'secondarySub.defaultMode': 'Secondary Subtitle Visibility Mode',
   'subtitlePosition.yPercent': 'Subtitle Position',
 };
@@ -150,6 +192,10 @@ const DESCRIPTION_OVERRIDES: Record<string, string> = {
     'Enable Lapis-specific mining behavior and sentence-card model targeting. When Kiku is enabled, Lapis features still work and Kiku-specific features are added on top.',
   'ankiConnect.isLapis.sentenceCardModel':
     'Anki note type used for Lapis sentence cards. Select from note types reported by AnkiConnect.',
+  'subtitleStyle.css':
+    'CSS declarations applied to primary subtitles. Includes color, background-color, and all font properties.',
+  'subtitleStyle.secondary.css':
+    'CSS declarations applied to secondary subtitles. Includes color, background-color, and all font properties.',
 };
 
 function isRecord(value: unknown): value is Record<string, unknown> {
@@ -215,6 +261,28 @@ function categoryAndSection(path: string): { category: ConfigSettingsCategory; s
   ) {
     return { category: 'behavior', section: 'Playback Pause Behavior' };
   }
+  if (path === 'subtitleStyle.preserveLineBreaks') {
+    return { category: 'behavior', section: 'Subtitle Behavior' };
+  }
+  if (
+    path === 'ankiConnect.knownWords.addMinedWordsImmediately' ||
+    path === 'ankiConnect.knownWords.decks' ||
+    path === 'ankiConnect.knownWords.matchMode' ||
+    path === 'ankiConnect.knownWords.refreshMinutes'
+  ) {
+    return { category: 'behavior', section: 'Known Words' };
+  }
+  if (path === 'ankiConnect.nPlusOne.minSentenceWords') {
+    return { category: 'behavior', section: 'N+1' };
+  }
+  if (
+    path === 'subtitleStyle.frequencyDictionary.matchMode' ||
+    path === 'subtitleStyle.frequencyDictionary.mode' ||
+    path === 'subtitleStyle.frequencyDictionary.sourcePath' ||
+    path === 'subtitleStyle.frequencyDictionary.topX'
+  ) {
+    return { category: 'behavior', section: 'Frequency Highlighting' };
+  }
   if (
     path.startsWith('ankiConnect.knownWords.') ||
     path.startsWith('ankiConnect.nPlusOne.') ||
@@ -243,7 +311,6 @@ function categoryAndSection(path: string): { category: ConfigSettingsCategory; s
       'subtitleSidebar.autoOpen',
       'subtitleSidebar.autoScroll',
       'subtitleSidebar.layout',
-      'subtitleSidebar.toggleKey',
     ]);
     return sidebarBehaviorPaths.has(path)
       ? { category: 'behavior', section: 'Subtitle Sidebar Behavior' }
@@ -259,7 +326,7 @@ function categoryAndSection(path: string): { category: ConfigSettingsCategory; s
     return { category: 'mining-anki', section: 'Media Capture' };
   }
   if (path.startsWith('ankiConnect.isKiku.') || path.startsWith('ankiConnect.isLapis.')) {
-    return { category: 'mining-anki', section: 'Kiku Features And Lapis Features' };
+    return { category: 'mining-anki', section: 'Kiku/Lapis Features' };
   }
   if (path.startsWith('ankiConnect.ai.')) {
     return { category: 'mining-anki', section: 'Anki AI' };
@@ -279,6 +346,9 @@ function categoryAndSection(path: string): { category: ConfigSettingsCategory; s
   ) {
     return { category: 'playback-sources', section: topSection(path) };
   }
+  if (path === 'stats.toggleKey' || path === 'stats.markWatchedKey') {
+    return { category: 'input', section: 'Overlay Shortcuts' };
+  }
   if (path.startsWith('shortcuts.')) {
     return { category: 'input', section: 'Overlay Shortcuts' };
   }
@@ -346,6 +416,7 @@ function topSection(path: string): string {
 
 function controlForPath(path: string, value: unknown): ConfigSettingsControl {
   if (SECRET_PATHS.has(path)) return 'secret';
+  if (getSubtitleCssScopeForPath(path)) return 'css-declarations';
   if (path === 'keybindings') return 'mpv-keybindings';
   if (path === 'ankiConnect.knownWords.decks') return 'known-words-decks';
   if (path === 'ankiConnect.isLapis.sentenceCardModel') return 'anki-note-type';
@@ -376,17 +447,71 @@ function controlForPath(path: string, value: unknown): ConfigSettingsControl {
 }
 
 function subsectionForPath(path: string): string | undefined {
-  if (path.startsWith('ankiConnect.knownWords.')) return 'Known Words';
-  if (path.startsWith('ankiConnect.nPlusOne.')) return 'N+1';
+  if (path === 'ankiConnect.knownWords.highlightEnabled') return 'Known Words';
+  if (path === 'ankiConnect.nPlusOne.enabled') return 'N+1';
   if (path === 'subtitleStyle.knownWordColor') return 'Known Words';
   if (path === 'subtitleStyle.nPlusOneColor') return 'N+1';
   if (path === 'subtitleStyle.enableJlpt' || path.startsWith('subtitleStyle.jlptColors.')) {
     return 'JLPT';
   }
-  if (path.startsWith('subtitleStyle.frequencyDictionary.')) return 'Frequency Dictionary';
+  if (
+    path === 'subtitleStyle.frequencyDictionary.enabled' ||
+    path === 'subtitleStyle.frequencyDictionary.singleColor' ||
+    path === 'subtitleStyle.frequencyDictionary.bandedColors'
+  ) {
+    return 'Frequency Highlighting';
+  }
   if (path === 'subtitleStyle.nameMatchEnabled' || path === 'subtitleStyle.nameMatchColor') {
     return 'Character Names';
   }
+  if (path === 'anilist.characterDictionary.collapsibleSections.description') {
+    return 'Default Fold State';
+  }
+  if (path === 'anilist.characterDictionary.collapsibleSections.characterInformation') {
+    return 'Default Fold State';
+  }
+  if (path === 'anilist.characterDictionary.collapsibleSections.voicedBy') {
+    return 'Default Fold State';
+  }
+  if (path === 'stats.toggleKey' || path === 'stats.markWatchedKey') {
+    return 'Toggle & Visibility';
+  }
+  if (path.startsWith('shortcuts.')) {
+    const leaf = path.split('.').at(-1) ?? '';
+    if (leaf === 'multiCopyTimeoutMs') return 'Timing';
+    if (
+      leaf === 'copySubtitle' ||
+      leaf === 'copySubtitleMultiple' ||
+      leaf === 'mineSentence' ||
+      leaf === 'mineSentenceMultiple' ||
+      leaf === 'updateLastCardFromClipboard' ||
+      leaf === 'triggerFieldGrouping' ||
+      leaf === 'markAudioCard'
+    ) {
+      return 'Mining & Clipboard';
+    }
+    if (
+      leaf === 'toggleVisibleOverlayGlobal' ||
+      leaf === 'toggleSubtitleSidebar' ||
+      leaf === 'toggleSecondarySub' ||
+      leaf === 'toggleStatsOverlay' ||
+      leaf === 'markWatched'
+    ) {
+      return 'Toggle & Visibility';
+    }
+    if (
+      leaf === 'openCharacterDictionary' ||
+      leaf === 'openRuntimeOptions' ||
+      leaf === 'openJimaku' ||
+      leaf === 'openSessionHelp' ||
+      leaf === 'openControllerSelect' ||
+      leaf === 'openControllerDebug'
+    ) {
+      return 'Open Panels';
+    }
+    if (leaf === 'triggerSubsync') return 'Playback';
+    return undefined;
+  }
   return undefined;
 }
 
@@ -418,9 +543,9 @@ function compareFields(a: ConfigSettingsField, b: ConfigSettingsField): number {
   const sectionName = a.section.localeCompare(b.section);
   if (sectionName !== 0) return sectionName;
 
-  const subsection =
-    (SUBSECTION_ORDER.get(a.subsection ?? '') ?? Number.MAX_SAFE_INTEGER) -
-    (SUBSECTION_ORDER.get(b.subsection ?? '') ?? Number.MAX_SAFE_INTEGER);
+  const aSubOrder = a.subsection === undefined ? -1 : (SUBSECTION_ORDER.get(a.subsection) ?? Number.MAX_SAFE_INTEGER);
+  const bSubOrder = b.subsection === undefined ? -1 : (SUBSECTION_ORDER.get(b.subsection) ?? Number.MAX_SAFE_INTEGER);
+  const subsection = aSubOrder - bSubOrder;
   if (subsection !== 0) return subsection;
 
   const subsectionName = (a.subsection ?? '').localeCompare(b.subsection ?? '');
@@ -446,7 +571,9 @@ function restartBehaviorForPath(path: string): ConfigSettingsRestartBehavior {
     pathStartsWith(path, 'subtitleStyle') ||
     pathStartsWith(path, 'subtitleSidebar') ||
     path === 'secondarySub.defaultMode' ||
-    pathStartsWith(path, 'ankiConnect.ai')
+    pathStartsWith(path, 'ankiConnect.ai') ||
+    path === 'stats.toggleKey' ||
+    path === 'stats.markWatchedKey'
   ) {
     return 'hot-reload';
   }
@@ -474,6 +601,7 @@ function fieldForLeaf(leaf: Leaf): ConfigSettingsField {
       leaf.path.startsWith('immersionTracking.retention.') ||
       leaf.path.startsWith('youtubeSubgen.'),
     secret: SECRET_PATHS.has(leaf.path),
+    settingsHidden: SUBTITLE_CSS_MANAGED_CONFIG_PATHS.has(leaf.path),
   };
 }
 
diff --git a/src/main.ts b/src/main.ts
index f58673df..ababe6b6 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -2576,7 +2576,7 @@ function shouldInitializeMecabForAnnotations(): boolean {
   const config = getResolvedConfig();
   const nPlusOneEnabled = getRuntimeBooleanOption(
     'subtitle.annotation.nPlusOne',
-    config.ankiConnect.knownWords.highlightEnabled,
+    config.ankiConnect.nPlusOne.enabled,
   );
   const jlptEnabled = getRuntimeBooleanOption(
     'subtitle.annotation.jlpt',
@@ -4187,7 +4187,7 @@ const {
       getNPlusOneEnabled: () =>
         getRuntimeBooleanOption(
           'subtitle.annotation.nPlusOne',
-          getResolvedConfig().ankiConnect.knownWords.highlightEnabled,
+          getResolvedConfig().ankiConnect.nPlusOne.enabled,
         ),
       getMinSentenceWordsForNPlusOne: () =>
         getResolvedConfig().ankiConnect.nPlusOne.minSentenceWords,
diff --git a/src/renderer/subtitle-render.test.ts b/src/renderer/subtitle-render.test.ts
index 932c3b11..5ce78dc8 100644
--- a/src/renderer/subtitle-render.test.ts
+++ b/src/renderer/subtitle-render.test.ts
@@ -426,6 +426,55 @@ test('applySubtitleStyle stores secondary background styles in hover-aware css v
   }
 });
 
+test('applySubtitleStyle applies primary and secondary css declaration objects', () => {
+  const restoreDocument = installFakeDocument();
+  try {
+    const subtitleRoot = new FakeElement('div');
+    const subtitleContainer = new FakeElement('div');
+    const secondarySubRoot = new FakeElement('div');
+    const secondarySubContainer = new FakeElement('div');
+    const ctx = {
+      state: createRendererState(),
+      dom: {
+        subtitleRoot,
+        subtitleContainer,
+        secondarySubRoot,
+        secondarySubContainer,
+      },
+    } as never;
+
+    const renderer = createSubtitleRenderer(ctx);
+    renderer.applySubtitleStyle({
+      fontSize: 35,
+      css: {
+        'font-size': '42px',
+        'text-wrap': 'balance',
+        '--subtitle-outline': '1px',
+      },
+      secondary: {
+        fontSize: 24,
+        css: {
+          'font-size': '28px',
+          'text-transform': 'uppercase',
+        },
+      },
+    } as never);
+
+    const primaryValues = (subtitleRoot.style as unknown as { values?: Map<string, string> })
+      .values;
+    const secondaryValues = (secondarySubRoot.style as unknown as { values?: Map<string, string> })
+      .values;
+
+    assert.equal(primaryValues?.get('font-size'), '42px');
+    assert.equal(primaryValues?.get('text-wrap'), 'balance');
+    assert.equal(primaryValues?.get('--subtitle-outline'), '1px');
+    assert.equal(secondaryValues?.get('font-size'), '28px');
+    assert.equal(secondaryValues?.get('text-transform'), 'uppercase');
+  } finally {
+    restoreDocument();
+  }
+});
+
 test('annotated subtitle tokens inherit configured base subtitle typography', () => {
   const restoreDocument = installFakeDocument();
   try {
diff --git a/src/renderer/subtitle-render.ts b/src/renderer/subtitle-render.ts
index f913bc36..e7dbf2aa 100644
--- a/src/renderer/subtitle-render.ts
+++ b/src/renderer/subtitle-render.ts
@@ -158,6 +158,32 @@ function applyInlineStyleDeclarations(
   }
 }
 
+function normalizeCssDeclarationObject(value: unknown): Record<string, string> {
+  if (!value || typeof value !== 'object' || Array.isArray(value)) {
+    return {};
+  }
+
+  const declarations: Record<string, string> = {};
+  for (const [key, rawValue] of Object.entries(value)) {
+    if (typeof rawValue !== 'string') continue;
+    const cssValue = rawValue.trim();
+    if (cssValue.length > 0) declarations[key] = cssValue;
+  }
+  return declarations;
+}
+
+function applySubtitleCssDeclarations(
+  root: HTMLElement,
+  container: HTMLElement,
+  declarations: Record<string, string>,
+): void {
+  applyInlineStyleDeclarations(root, declarations, CONTAINER_STYLE_KEYS);
+  applyInlineStyleDeclarations(
+    container,
+    pickInlineStyleDeclarations(declarations, CONTAINER_STYLE_KEYS),
+  );
+}
+
 function pickInlineStyleDeclarations(
   declarations: Record<string, unknown>,
   includedKeys: ReadonlySet<string>,
@@ -172,7 +198,9 @@ function pickInlineStyleDeclarations(
 
 const CONTAINER_STYLE_KEYS = new Set<string>([
   'background',
+  'background-color',
   'backgroundColor',
+  'backdrop-filter',
   'backdropFilter',
   'WebkitBackdropFilter',
   'webkitBackdropFilter',
@@ -180,7 +208,7 @@ const CONTAINER_STYLE_KEYS = new Set<string>([
 ]);
 
 function resolveSecondaryBackgroundColor(declarations: Record<string, unknown>): string {
-  for (const key of ['backgroundColor', 'background']) {
+  for (const key of ['backgroundColor', 'background-color', 'background']) {
     const value = declarations[key];
     if (typeof value === 'string' && value.trim().length > 0) {
       return value.trim();
@@ -193,6 +221,7 @@ function resolveSecondaryBackgroundColor(declarations: Record<string, unknown>):
 function resolveSecondaryBackdropFilter(declarations: Record<string, unknown>): string {
   for (const key of [
     'backdropFilter',
+    'backdrop-filter',
     'WebkitBackdropFilter',
     'webkitBackdropFilter',
     '-webkit-backdrop-filter',
@@ -762,20 +791,26 @@ export function createSubtitleRenderer(ctx: RendererContext) {
       '--subtitle-frequency-band-5-color',
       frequencyBandedColors[4],
     );
+    applySubtitleCssDeclarations(
+      ctx.dom.subtitleRoot,
+      ctx.dom.subtitleContainer,
+      normalizeCssDeclarationObject(style.css),
+    );
 
     const secondaryStyle = style.secondary;
     if (!secondaryStyle) return;
 
     const secondaryStyleDeclarations = secondaryStyle as Record<string, unknown>;
+    const secondaryCssDeclarations = normalizeCssDeclarationObject(secondaryStyle.css);
     applyInlineStyleDeclarations(
       ctx.dom.secondarySubRoot,
       secondaryStyleDeclarations,
       CONTAINER_STYLE_KEYS,
     );
-    const secondaryContainerStyleDeclarations = pickInlineStyleDeclarations(
-      secondaryStyleDeclarations,
-      CONTAINER_STYLE_KEYS,
-    );
+    const secondaryContainerStyleDeclarations = {
+      ...pickInlineStyleDeclarations(secondaryStyleDeclarations, CONTAINER_STYLE_KEYS),
+      ...pickInlineStyleDeclarations(secondaryCssDeclarations, CONTAINER_STYLE_KEYS),
+    };
     ctx.dom.secondarySubContainer.style.setProperty(
       '--secondary-sub-background-color',
       resolveSecondaryBackgroundColor(secondaryContainerStyleDeclarations),
@@ -800,6 +835,11 @@ export function createSubtitleRenderer(ctx: RendererContext) {
     if (secondaryStyle.fontStyle) {
       ctx.dom.secondarySubRoot.style.fontStyle = secondaryStyle.fontStyle;
     }
+    applySubtitleCssDeclarations(
+      ctx.dom.secondarySubRoot,
+      ctx.dom.secondarySubContainer,
+      secondaryCssDeclarations,
+    );
   }
 
   return {
diff --git a/src/settings/index.html b/src/settings/index.html
index 28aa6c8b..31bafc3a 100644
--- a/src/settings/index.html
+++ b/src/settings/index.html
@@ -33,7 +33,6 @@
               placeholder="Search"
               aria-label="Search settings"
             />
-            <button id="openFileButton" class="secondary-button" type="button">Open File</button>
             <button id="saveButton" class="primary-button" type="button" disabled>Save</button>
           </div>
         </header>
diff --git a/src/settings/settings-anki-controls.test.ts b/src/settings/settings-anki-controls.test.ts
new file mode 100644
index 00000000..3f569eca
--- /dev/null
+++ b/src/settings/settings-anki-controls.test.ts
@@ -0,0 +1,31 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import * as ankiControls from './settings-anki-controls';
+
+test('note field model preference chooses Kiku before configured Lapis default', () => {
+  assert.equal(
+    ankiControls.selectPreferredNoteFieldModelName(['Lapis Morph', 'Kiku'], 'Lapis Morph'),
+    'Kiku',
+  );
+});
+
+test('note field model preference falls back to Lapis when Kiku is unavailable', () => {
+  assert.equal(
+    ankiControls.selectPreferredNoteFieldModelName(['Mining', 'Lapis Morph'], 'Lapis Morph'),
+    'Lapis Morph',
+  );
+});
+
+test('note field model preference does not treat partial Kiku matches as Kiku', () => {
+  assert.equal(
+    ankiControls.selectPreferredNoteFieldModelName(['Kikuchi', 'Lapis Morph'], 'Lapis Morph'),
+    'Lapis Morph',
+  );
+});
+
+test('note field model preference stays blank when no Kiku or Lapis note type exists', () => {
+  assert.equal(
+    ankiControls.selectPreferredNoteFieldModelName(['Basic', 'Mining'], 'Lapis Morph'),
+    '',
+  );
+});
diff --git a/src/settings/settings-anki-controls.ts b/src/settings/settings-anki-controls.ts
index 29ed6a49..8a70c036 100644
--- a/src/settings/settings-anki-controls.ts
+++ b/src/settings/settings-anki-controls.ts
@@ -17,6 +17,7 @@ const state: {
   modelFieldNamesErrors: Map<string, string>;
   noteFieldModelName: string;
   ankiConnectUrl: string;
+  noteFieldModelNameManuallySelected: boolean;
 } = {
   deckNames: null,
   deckNamesLoading: false,
@@ -32,6 +33,7 @@ const state: {
   modelFieldNamesErrors: new Map(),
   noteFieldModelName: '',
   ankiConnectUrl: '',
+  noteFieldModelNameManuallySelected: false,
 };
 
 let requestRender = (): void => undefined;
@@ -42,11 +44,32 @@ export function configureAnkiControls(options: { requestRender: () => void }): v
 
 export function initializeAnkiControls(values: Record<string, ConfigSettingsSnapshotValue>): void {
   const configuredNoteType = values['ankiConnect.isLapis.sentenceCardModel'];
-  if (!state.noteFieldModelName && typeof configuredNoteType === 'string') {
+  if (
+    !state.noteFieldModelName &&
+    !state.noteFieldModelNameManuallySelected &&
+    typeof configuredNoteType === 'string'
+  ) {
     state.noteFieldModelName = configuredNoteType;
   }
 }
 
+export function selectPreferredNoteFieldModelName(
+  modelNames: readonly string[],
+  _currentModelName = '',
+): string {
+  const exactKiku = modelNames.find((name) => name.toLowerCase() === 'kiku');
+  if (exactKiku) {
+    return exactKiku;
+  }
+
+  const lapis = modelNames.find((name) => name.toLowerCase().includes('lapis'));
+  if (lapis) {
+    return lapis;
+  }
+
+  return '';
+}
+
 function normalizeStringArray(value: unknown): string[] {
   return Array.isArray(value)
     ? value.filter((entry): entry is string => typeof entry === 'string' && entry.length > 0)
@@ -168,8 +191,11 @@ async function loadAnkiModelNames(draftUrl?: string): Promise<void> {
     if (result.ok) {
       state.modelNames = uniqueSorted(result.values);
       state.modelNamesError = null;
-      if (!state.noteFieldModelName && state.modelNames[0]) {
-        state.noteFieldModelName = state.modelNames[0];
+      if (!state.noteFieldModelNameManuallySelected) {
+        state.noteFieldModelName = selectPreferredNoteFieldModelName(
+          state.modelNames,
+          state.noteFieldModelName,
+        );
       }
     } else {
       state.modelNames = [];
@@ -318,6 +344,7 @@ export function renderNoteFieldModelPicker(context: SettingsControlContext): HTM
   select.value = state.noteFieldModelName;
   select.addEventListener('change', () => {
     state.noteFieldModelName = select.value;
+    state.noteFieldModelNameManuallySelected = true;
     requestRender();
   });
   control.append(select);
diff --git a/src/settings/settings-control-context.ts b/src/settings/settings-control-context.ts
index 99f696d2..42f19c99 100644
--- a/src/settings/settings-control-context.ts
+++ b/src/settings/settings-control-context.ts
@@ -2,6 +2,7 @@ import type { ConfigSettingsField, ConfigSettingsSnapshotValue } from '../types/
 
 export interface SettingsControlContext {
   setFieldError(path: string, message: string | null): void;
+  resetDraftPath(path: string, defaultValue?: ConfigSettingsSnapshotValue): void;
   updateDraft(path: string, value: ConfigSettingsSnapshotValue): void;
   valueForField(field: ConfigSettingsField): ConfigSettingsSnapshotValue;
   valueForPath(path: string): ConfigSettingsSnapshotValue | undefined;
diff --git a/src/settings/settings-controls.ts b/src/settings/settings-controls.ts
index 331f4687..8da7c7c3 100644
--- a/src/settings/settings-controls.ts
+++ b/src/settings/settings-controls.ts
@@ -10,12 +10,23 @@ import {
 } from './settings-anki-controls';
 import type { SettingsControlContext } from './settings-control-context';
 import { createElement, isSecretSnapshotValue } from './settings-control-dom';
-import { renderKeyboardInput, renderMpvKeybindingsInput } from './settings-keybinding-controls';
+import {
+  configureKeybindingControls,
+  renderKeyboardInput,
+  renderMpvKeybindingsInput,
+} from './settings-keybinding-controls';
+import {
+  getSubtitleCssManagedConfigPaths,
+  getSubtitleCssScopeForPath,
+  parseSubtitleCssDeclarations,
+  serializeSubtitleCssDeclarations,
+} from './subtitle-style-css';
 
 export { renderNoteFieldModelPicker };
 
 export function configureSettingsControls(options: { requestRender: () => void }): void {
   configureAnkiControls(options);
+  configureKeybindingControls(options);
 }
 
 export function initializeSettingsControls(
@@ -90,6 +101,44 @@ function renderStringListInput(
   return textarea;
 }
 
+function renderCssDeclarationsInput(
+  context: SettingsControlContext,
+  field: ConfigSettingsField,
+): HTMLElement {
+  const scope = getSubtitleCssScopeForPath(field.configPath);
+  const textarea = createElement(
+    'textarea',
+    'config-textarea css-declarations',
+  ) as HTMLTextAreaElement;
+  textarea.spellcheck = false;
+  if (!scope) return textarea;
+
+  const managedPaths = getSubtitleCssManagedConfigPaths(scope);
+  const values: Record<string, ConfigSettingsSnapshotValue | undefined> = {
+    [field.configPath]: context.valueForPath(field.configPath),
+  };
+  for (const path of managedPaths) {
+    values[path] = context.valueForPath(path);
+  }
+  textarea.value = serializeSubtitleCssDeclarations(scope, values);
+  textarea.addEventListener('input', () => {
+    const parsed = parseSubtitleCssDeclarations(textarea.value);
+    if (!parsed.ok) {
+      textarea.classList.add('invalid');
+      context.setFieldError(field.configPath, parsed.error);
+      return;
+    }
+
+    textarea.classList.remove('invalid');
+    context.setFieldError(field.configPath, null);
+    context.updateDraft(field.configPath, parsed.declarations);
+    for (const path of managedPaths) {
+      context.resetDraftPath(path, undefined);
+    }
+  });
+  return textarea;
+}
+
 export function renderControl(
   field: ConfigSettingsField,
   context: SettingsControlContext,
@@ -134,7 +183,13 @@ export function renderControl(
   if (field.control === 'number') {
     const input = createElement('input', 'config-input') as HTMLInputElement;
     input.type = 'number';
-    input.value = typeof value === 'number' ? String(value) : '';
+    const numericValue =
+      typeof value === 'number'
+        ? value
+        : typeof field.defaultValue === 'number'
+          ? field.defaultValue
+          : NaN;
+    input.value = Number.isFinite(numericValue) ? String(numericValue) : '';
     input.addEventListener('input', () => {
       const next = parseOptionalNumberInputValue(input.value);
       if (next.ok) {
@@ -174,6 +229,10 @@ export function renderControl(
     return renderJsonInput(context, field, value);
   }
 
+  if (field.control === 'css-declarations') {
+    return renderCssDeclarationsInput(context, field);
+  }
+
   if (field.control === 'textarea') {
     const textarea = createElement('textarea', 'config-textarea compact') as HTMLTextAreaElement;
     textarea.spellcheck = false;
diff --git a/src/settings/settings-keybinding-controls.ts b/src/settings/settings-keybinding-controls.ts
index 9e0f3672..be00bea8 100644
--- a/src/settings/settings-keybinding-controls.ts
+++ b/src/settings/settings-keybinding-controls.ts
@@ -12,6 +12,11 @@ import type { SettingsControlContext } from './settings-control-context';
 import { createElement } from './settings-control-dom';
 
 let activeKeyLearningStop: (() => void) | null = null;
+let requestRender = (): void => undefined;
+
+export function configureKeybindingControls(options: { requestRender: () => void }): void {
+  requestRender = options.requestRender;
+}
 
 function startKeyLearning(
   button: HTMLButtonElement,
@@ -107,7 +112,8 @@ export function renderMpvKeybindingsInput(
   const rows = createMpvKeybindingRows(DEFAULT_KEYBINDINGS, context.valueForField(field));
   const container = createElement('div', 'keybinding-editor');
 
-  for (const row of rows) {
+  for (let i = 0; i < rows.length; i++) {
+    const row = rows[i]!;
     const item = createElement('div', 'keybinding-row');
     const keyButton = renderKeyLearnButton(row.key, 'dom-code', (next) => {
       row.key = next;
@@ -130,9 +136,27 @@ export function renderMpvKeybindingsInput(
       row.commandText = command.value;
       applyMpvRows(context, field, rows);
     });
-    item.append(keyButton, command);
+    const removeButton = createElement('button', 'reset-button icon-button') as HTMLButtonElement;
+    removeButton.type = 'button';
+    removeButton.textContent = 'Remove';
+    removeButton.addEventListener('click', () => {
+      rows.splice(i, 1);
+      applyMpvRows(context, field, rows);
+      requestRender();
+    });
+    item.append(keyButton, command, removeButton);
     container.append(item);
   }
 
+  const addButton = createElement('button', 'secondary-button compact-button') as HTMLButtonElement;
+  addButton.type = 'button';
+  addButton.textContent = 'Add Binding';
+  addButton.addEventListener('click', () => {
+    rows.push({ defaultKey: '', key: '', command: null, commandText: '', isDefault: false });
+    applyMpvRows(context, field, rows);
+    requestRender();
+  });
+  container.append(addButton);
+
   return container;
 }
diff --git a/src/settings/settings-markup.test.ts b/src/settings/settings-markup.test.ts
new file mode 100644
index 00000000..1e8bb25e
--- /dev/null
+++ b/src/settings/settings-markup.test.ts
@@ -0,0 +1,11 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import fs from 'node:fs';
+import path from 'node:path';
+
+test('settings toolbar does not expose an open file button', () => {
+  const html = fs.readFileSync(path.join(process.cwd(), 'src/settings/index.html'), 'utf8');
+
+  assert.equal(html.includes('id="openFileButton"'), false);
+  assert.equal(html.includes('Open File'), false);
+});
diff --git a/src/settings/settings-model.test.ts b/src/settings/settings-model.test.ts
index e91213be..b1df8af0 100644
--- a/src/settings/settings-model.test.ts
+++ b/src/settings/settings-model.test.ts
@@ -4,6 +4,7 @@ import {
   createSettingsDraft,
   filterSettingsFields,
   setDraftValue,
+  resetDraftPath,
   getDirtyOperations,
 } from './settings-model';
 import type { ConfigSettingsField } from '../types/settings';
@@ -31,6 +32,18 @@ const fields: ConfigSettingsField[] = [
     defaultValue: true,
     restartBehavior: 'restart',
   },
+  {
+    id: 'subtitleStyle.fontSize',
+    label: 'Font Size',
+    description: 'Hidden behind CSS editor.',
+    configPath: 'subtitleStyle.fontSize',
+    category: 'appearance',
+    section: 'Primary Subtitle Appearance',
+    control: 'number',
+    defaultValue: 35,
+    restartBehavior: 'hot-reload',
+    settingsHidden: true,
+  },
 ];
 
 test('filterSettingsFields searches label, section, and config path', () => {
@@ -41,6 +54,16 @@ test('filterSettingsFields searches label, section, and config path', () => {
     ['subtitleStyle.autoPauseVideoOnHover'],
   );
   assert.deepEqual(filterSettingsFields(fields, { category: 'behavior', query: 'anki' }), []);
+  assert.deepEqual(
+    filterSettingsFields(fields, { query: 'anki' }).map((field) => field.configPath),
+    ['ankiConnect.enabled'],
+  );
+  assert.deepEqual(
+    filterSettingsFields(fields, { query: 'pause hover' }).map((field) => field.configPath),
+    ['subtitleStyle.autoPauseVideoOnHover'],
+  );
+  assert.deepEqual(filterSettingsFields(fields, { query: 'pause anki' }), []);
+  assert.deepEqual(filterSettingsFields(fields, { category: 'appearance', query: '' }), []);
 });
 
 test('settings draft tracks dirty set and emits save operations', () => {
@@ -60,3 +83,25 @@ test('settings draft tracks dirty set and emits save operations', () => {
   setDraftValue(draft, 'subtitleStyle.autoPauseVideoOnHover', true);
   assert.deepEqual(getDirtyOperations(draft), []);
 });
+
+test('settings draft emits reset operations for css-editor-owned legacy style paths', () => {
+  const draft = createSettingsDraft({
+    'subtitleStyle.css': {},
+    'subtitleStyle.fontSize': 35,
+  });
+
+  setDraftValue(draft, 'subtitleStyle.css', { 'font-size': '42px' });
+  resetDraftPath(draft, 'subtitleStyle.fontSize', undefined);
+
+  assert.deepEqual(getDirtyOperations(draft), [
+    {
+      op: 'set',
+      path: 'subtitleStyle.css',
+      value: { 'font-size': '42px' },
+    },
+    {
+      op: 'reset',
+      path: 'subtitleStyle.fontSize',
+    },
+  ]);
+});
diff --git a/src/settings/settings-model.ts b/src/settings/settings-model.ts
index 29f4fada..1d7bc5af 100644
--- a/src/settings/settings-model.ts
+++ b/src/settings/settings-model.ts
@@ -6,7 +6,7 @@ import type {
 } from '../types/settings';
 
 export interface SettingsFilter {
-  category: ConfigSettingsCategory;
+  category?: ConfigSettingsCategory;
   query?: string;
 }
 
@@ -20,6 +20,15 @@ function normalizeQuery(query: string | undefined): string {
   return (query ?? '').trim().toLowerCase();
 }
 
+function searchableText(parts: Array<string | undefined>): string {
+  return parts
+    .filter(Boolean)
+    .join(' ')
+    .replace(/([a-z0-9])([A-Z])/g, '$1 $2')
+    .replace(/[^a-zA-Z0-9]+/g, ' ')
+    .toLowerCase();
+}
+
 function valuesEqual(a: unknown, b: unknown): boolean {
   return JSON.stringify(a) === JSON.stringify(b);
 }
@@ -29,24 +38,26 @@ export function filterSettingsFields(
   filter: SettingsFilter,
 ): ConfigSettingsField[] {
   const query = normalizeQuery(filter.query);
+  const terms = query.length > 0 ? query.split(/\s+/) : [];
   return fields.filter((field) => {
-    if (field.category !== filter.category || field.legacyHidden) {
+    if (field.legacyHidden || field.settingsHidden) {
+      return false;
+    }
+    if (filter.category && field.category !== filter.category) {
       return false;
     }
     if (!query) {
       return true;
     }
-    const haystack = [
+    const haystack = searchableText([
       field.label,
       field.description,
       field.configPath,
       field.section,
       field.subsection ?? '',
       field.enumValues?.join(' ') ?? '',
-    ]
-      .join(' ')
-      .toLowerCase();
-    return haystack.includes(query);
+    ]);
+    return terms.every((term) => haystack.includes(term));
   });
 }
 
diff --git a/src/settings/settings.ts b/src/settings/settings.ts
index e104b3c1..1c998ca8 100644
--- a/src/settings/settings.ts
+++ b/src/settings/settings.ts
@@ -20,6 +20,7 @@ import {
   setDraftValue,
   type SettingsDraft,
 } from './settings-model';
+import { getSubtitleCssManagedConfigPaths, getSubtitleCssScopeForPath } from './subtitle-style-css';
 
 declare global {
   interface Window {
@@ -76,7 +77,6 @@ const dom = {
   categoryTitle: getElement<HTMLHeadingElement>('categoryTitle'),
   categoryMeta: getElement<HTMLElement>('categoryMeta'),
   searchInput: getElement<HTMLInputElement>('searchInput'),
-  openFileButton: getElement<HTMLButtonElement>('openFileButton'),
   saveButton: getElement<HTMLButtonElement>('saveButton'),
   statusBanner: getElement<HTMLElement>('statusBanner'),
   warningsPanel: getElement<HTMLElement>('warningsPanel'),
@@ -163,6 +163,13 @@ function updateDraft(path: string, value: ConfigSettingsSnapshotValue): void {
   syncSaveButton();
 }
 
+function resetDraftPathContext(path: string, defaultValue?: ConfigSettingsSnapshotValue): void {
+  if (!state.draft) return;
+  resetDraftPath(state.draft, path, defaultValue);
+  state.inputErrors.delete(path);
+  syncSaveButton();
+}
+
 function renderWarnings(snapshot: ConfigSettingsSnapshot): void {
   dom.warningsPanel.replaceChildren();
   if (snapshot.warnings.length === 0) {
@@ -192,7 +199,7 @@ function renderCategoryNav(snapshot: ConfigSettingsSnapshot): void {
   dom.categoryNav.replaceChildren();
   for (const category of CATEGORY_ORDER) {
     const count = snapshot.fields.filter(
-      (field) => field.category === category && !field.legacyHidden,
+      (field) => field.category === category && !field.legacyHidden && !field.settingsHidden,
     ).length;
     if (count === 0) continue;
     const button = createElement('button', 'category-button') as HTMLButtonElement;
@@ -206,6 +213,7 @@ function renderCategoryNav(snapshot: ConfigSettingsSnapshot): void {
     button.addEventListener('click', () => {
       state.category = category;
       render();
+      dom.settingsContent.scrollTop = 0;
     });
     dom.categoryNav.append(button);
   }
@@ -222,7 +230,13 @@ function renderField(field: ConfigSettingsField): HTMLElement {
 
   const controlWrap = createElement('div', 'field-control');
   controlWrap.append(
-    renderControl(field, { setFieldError, updateDraft, valueForField, valueForPath }),
+    renderControl(field, {
+      setFieldError,
+      resetDraftPath: resetDraftPathContext,
+      updateDraft,
+      valueForField,
+      valueForPath,
+    }),
   );
   const resetButton = createElement('button', 'reset-button') as HTMLButtonElement;
   resetButton.type = 'button';
@@ -230,6 +244,12 @@ function renderField(field: ConfigSettingsField): HTMLElement {
   resetButton.addEventListener('click', () => {
     if (!state.draft) return;
     resetDraftPath(state.draft, field.configPath, field.defaultValue);
+    const cssScope = getSubtitleCssScopeForPath(field.configPath);
+    if (cssScope) {
+      for (const path of getSubtitleCssManagedConfigPaths(cssScope)) {
+        resetDraftPath(state.draft, path, undefined);
+      }
+    }
     state.inputErrors.delete(field.configPath);
     render();
   });
@@ -240,13 +260,24 @@ function renderField(field: ConfigSettingsField): HTMLElement {
 
 function renderSettingsContent(snapshot: ConfigSettingsSnapshot): void {
   dom.settingsContent.replaceChildren();
+  const query = state.query.trim();
   const fields = filterSettingsFields(snapshot.fields, {
-    category: state.category,
-    query: state.query,
+    category: query ? undefined : state.category,
+    query,
   });
 
-  dom.categoryTitle.textContent = CATEGORY_LABELS[state.category];
-  dom.categoryMeta.textContent = `${fields.length} setting${fields.length === 1 ? '' : 's'}`;
+  if (query) {
+    const categoryCount = new Set(fields.map((field) => field.category)).size;
+    dom.categoryTitle.textContent = 'Search results';
+    dom.categoryMeta.textContent = `${fields.length} setting${fields.length === 1 ? '' : 's'}${
+      categoryCount > 0
+        ? ` across ${categoryCount} categor${categoryCount === 1 ? 'y' : 'ies'}`
+        : ''
+    }`;
+  } else {
+    dom.categoryTitle.textContent = CATEGORY_LABELS[state.category];
+    dom.categoryMeta.textContent = `${fields.length} setting${fields.length === 1 ? '' : 's'}`;
+  }
 
   if (fields.length === 0) {
     const empty = createElement('div', 'empty-state');
@@ -255,25 +286,35 @@ function renderSettingsContent(snapshot: ConfigSettingsSnapshot): void {
     return;
   }
 
-  const sections = new Map<string, ConfigSettingsField[]>();
+  const sections = new Map<
+    string,
+    { title: string; rawSection: string; fields: ConfigSettingsField[] }
+  >();
   for (const field of fields) {
-    const sectionFields = sections.get(field.section) ?? [];
-    sectionFields.push(field);
-    sections.set(field.section, sectionFields);
+    const title = query ? `${CATEGORY_LABELS[field.category]} / ${field.section}` : field.section;
+    const section = sections.get(title) ?? { title, rawSection: field.section, fields: [] };
+    section.fields.push(field);
+    sections.set(title, section);
   }
 
-  for (const [section, sectionFields] of sections) {
+  for (const section of sections.values()) {
     const sectionEl = createElement('section', 'settings-section');
     const title = createElement('h2');
-    title.textContent = section;
+    title.textContent = section.title;
     sectionEl.append(title);
-    if (section === 'Note Fields') {
+    if (section.rawSection === 'Note Fields') {
       sectionEl.append(
-        renderNoteFieldModelPicker({ setFieldError, updateDraft, valueForField, valueForPath }),
+        renderNoteFieldModelPicker({
+          setFieldError,
+          resetDraftPath: resetDraftPathContext,
+          updateDraft,
+          valueForField,
+          valueForPath,
+        }),
       );
     }
     let currentSubsection = '';
-    for (const field of sectionFields) {
+    for (const field of section.fields) {
       if (field.subsection && field.subsection !== currentSubsection) {
         currentSubsection = field.subsection;
         const subsectionTitle = createElement('h3', 'settings-subsection-title');
@@ -353,11 +394,6 @@ dom.searchInput.addEventListener('input', () => {
 dom.saveButton.addEventListener('click', () => {
   void save();
 });
-dom.openFileButton.addEventListener('click', () => {
-  void window.configSettingsAPI.openSettingsFile().catch((error) => {
-    setStatus(error instanceof Error ? error.message : 'Failed to open settings file', 'error');
-  });
-});
 
 void loadSnapshot().catch((error) => {
   setStatus(error instanceof Error ? error.message : 'Failed to load settings', 'error');
diff --git a/src/settings/style.css b/src/settings/style.css
index 9acb347c..dab0a054 100644
--- a/src/settings/style.css
+++ b/src/settings/style.css
@@ -262,7 +262,7 @@ h1 {
 }
 
 .search-input {
-  width: 210px;
+  width: min(360px, 34vw);
   height: 36px;
   padding: 0 12px;
 }
@@ -296,6 +296,12 @@ h1 {
   min-height: 86px;
 }
 
+.config-textarea.css-declarations {
+  width: min(560px, 100%);
+  min-height: 188px;
+  tab-size: 2;
+}
+
 .search-input:hover,
 .config-input:hover,
 .config-textarea:hover {
@@ -675,7 +681,7 @@ code {
 
 .keybinding-row {
   display: grid;
-  grid-template-columns: minmax(146px, 0.78fr) minmax(220px, 1.22fr);
+  grid-template-columns: minmax(146px, 0.78fr) minmax(180px, 1.22fr) auto;
   gap: 8px;
   align-items: start;
 }
diff --git a/src/settings/subtitle-style-css.test.ts b/src/settings/subtitle-style-css.test.ts
new file mode 100644
index 00000000..5553526d
--- /dev/null
+++ b/src/settings/subtitle-style-css.test.ts
@@ -0,0 +1,88 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+
+import {
+  getSubtitleCssManagedConfigPaths,
+  parseSubtitleCssDeclarations,
+  serializeSubtitleCssDeclarations,
+} from './subtitle-style-css';
+
+test('serializeSubtitleCssDeclarations builds primary CSS from config minus default colors', () => {
+  const css = serializeSubtitleCssDeclarations('primary', {
+    'subtitleStyle.fontFamily': 'M PLUS 1, sans-serif',
+    'subtitleStyle.fontSize': 35,
+    'subtitleStyle.fontColor': '#cad3f5',
+    'subtitleStyle.backgroundColor': 'transparent',
+    'subtitleStyle.textShadow': '0 2px 6px rgba(0,0,0,0.9)',
+    'subtitleStyle.css': {
+      filter: 'drop-shadow(0 0 8px #000)',
+      '--subtitle-outline': '1px',
+    },
+  });
+
+  assert.match(css, /font-family: M PLUS 1, sans-serif;/);
+  assert.match(css, /font-size: 35px;/);
+  assert.match(css, /text-shadow: 0 2px 6px rgba\(0,0,0,0.9\);/);
+  assert.match(css, /filter: drop-shadow\(0 0 8px #000\);/);
+  assert.match(css, /--subtitle-outline: 1px;/);
+  assert.doesNotMatch(css, /^color:/m);
+  assert.doesNotMatch(css, /^background-color:/m);
+});
+
+test('serializeSubtitleCssDeclarations builds secondary CSS from secondary config paths', () => {
+  const css = serializeSubtitleCssDeclarations('secondary', {
+    'subtitleStyle.secondary.fontFamily': 'Noto Sans, sans-serif',
+    'subtitleStyle.secondary.fontSize': 24,
+    'subtitleStyle.secondary.fontColor': '#cad3f5',
+    'subtitleStyle.secondary.backgroundColor': 'transparent',
+    'subtitleStyle.secondary.css': {
+      'text-transform': 'uppercase',
+    },
+  });
+
+  assert.match(css, /font-family: Noto Sans, sans-serif;/);
+  assert.match(css, /font-size: 24px;/);
+  assert.match(css, /text-transform: uppercase;/);
+  assert.doesNotMatch(css, /^color:/m);
+  assert.doesNotMatch(css, /^background-color:/m);
+});
+
+test('parseSubtitleCssDeclarations accepts arbitrary declaration properties', () => {
+  assert.deepEqual(
+    parseSubtitleCssDeclarations(`
+      font-size: 40px;
+      text-wrap: balance;
+      -webkit-text-stroke: 1px black;
+      --subtitle-outline: 1px;
+    `),
+    {
+      ok: true,
+      declarations: {
+        'font-size': '40px',
+        'text-wrap': 'balance',
+        '-webkit-text-stroke': '1px black',
+        '--subtitle-outline': '1px',
+      },
+    },
+  );
+});
+
+test('parseSubtitleCssDeclarations rejects selectors and malformed declarations', () => {
+  assert.equal(parseSubtitleCssDeclarations('#subtitleRoot { font-size: 40px; }').ok, false);
+  assert.equal(parseSubtitleCssDeclarations('font-size 40px;').ok, false);
+});
+
+test('getSubtitleCssManagedConfigPaths excludes color controls', () => {
+  assert.ok(getSubtitleCssManagedConfigPaths('primary').includes('subtitleStyle.fontSize'));
+  assert.ok(
+    getSubtitleCssManagedConfigPaths('secondary').includes('subtitleStyle.secondary.fontSize'),
+  );
+  assert.equal(
+    getSubtitleCssManagedConfigPaths('primary').includes('subtitleStyle.fontColor'),
+    false,
+  );
+  assert.equal(
+    getSubtitleCssManagedConfigPaths('secondary').includes('subtitleStyle.secondary.fontColor'),
+    false,
+  );
+});
diff --git a/src/settings/subtitle-style-css.ts b/src/settings/subtitle-style-css.ts
new file mode 100644
index 00000000..1f0a23f6
--- /dev/null
+++ b/src/settings/subtitle-style-css.ts
@@ -0,0 +1,302 @@
+import type { ConfigSettingsSnapshotValue } from '../types/settings';
+
+export type SubtitleCssScope = 'primary' | 'secondary';
+
+type LegacyCssDeclaration = {
+  property: string;
+  primaryPath: string;
+  secondaryPath: string;
+  format?: (value: unknown) => string | undefined;
+};
+
+export type SubtitleCssParseResult =
+  | { ok: true; declarations: Record<string, string> }
+  | { ok: false; error: string };
+
+const LEGACY_CSS_DECLARATIONS: LegacyCssDeclaration[] = [
+  {
+    property: 'font-family',
+    primaryPath: 'subtitleStyle.fontFamily',
+    secondaryPath: 'subtitleStyle.secondary.fontFamily',
+  },
+  {
+    property: 'font-size',
+    primaryPath: 'subtitleStyle.fontSize',
+    secondaryPath: 'subtitleStyle.secondary.fontSize',
+    format: formatCssLengthLikeValue,
+  },
+  {
+    property: 'font-weight',
+    primaryPath: 'subtitleStyle.fontWeight',
+    secondaryPath: 'subtitleStyle.secondary.fontWeight',
+  },
+  {
+    property: 'font-style',
+    primaryPath: 'subtitleStyle.fontStyle',
+    secondaryPath: 'subtitleStyle.secondary.fontStyle',
+  },
+  {
+    property: 'line-height',
+    primaryPath: 'subtitleStyle.lineHeight',
+    secondaryPath: 'subtitleStyle.secondary.lineHeight',
+  },
+  {
+    property: 'letter-spacing',
+    primaryPath: 'subtitleStyle.letterSpacing',
+    secondaryPath: 'subtitleStyle.secondary.letterSpacing',
+  },
+  {
+    property: 'word-spacing',
+    primaryPath: 'subtitleStyle.wordSpacing',
+    secondaryPath: 'subtitleStyle.secondary.wordSpacing',
+  },
+  {
+    property: 'font-kerning',
+    primaryPath: 'subtitleStyle.fontKerning',
+    secondaryPath: 'subtitleStyle.secondary.fontKerning',
+  },
+  {
+    property: 'text-rendering',
+    primaryPath: 'subtitleStyle.textRendering',
+    secondaryPath: 'subtitleStyle.secondary.textRendering',
+  },
+  {
+    property: 'text-shadow',
+    primaryPath: 'subtitleStyle.textShadow',
+    secondaryPath: 'subtitleStyle.secondary.textShadow',
+  },
+  {
+    property: 'backdrop-filter',
+    primaryPath: 'subtitleStyle.backdropFilter',
+    secondaryPath: 'subtitleStyle.secondary.backdropFilter',
+  },
+  {
+    property: 'color',
+    primaryPath: 'subtitleStyle.fontColor',
+    secondaryPath: 'subtitleStyle.secondary.fontColor',
+  },
+  {
+    property: 'background-color',
+    primaryPath: 'subtitleStyle.backgroundColor',
+    secondaryPath: 'subtitleStyle.secondary.backgroundColor',
+  },
+];
+
+const CSS_PROPERTY_PATTERN = /^(?:--[A-Za-z0-9_-]+|-?[A-Za-z][A-Za-z0-9_-]*)$/;
+
+export function getSubtitleCssPath(scope: SubtitleCssScope): string {
+  return scope === 'primary' ? 'subtitleStyle.css' : 'subtitleStyle.secondary.css';
+}
+
+export function getSubtitleCssManagedConfigPaths(scope: SubtitleCssScope): string[] {
+  return LEGACY_CSS_DECLARATIONS.map((declaration) =>
+    scope === 'primary' ? declaration.primaryPath : declaration.secondaryPath,
+  );
+}
+
+export function getSubtitleCssScopeForPath(path: string): SubtitleCssScope | null {
+  if (path === 'subtitleStyle.css') return 'primary';
+  if (path === 'subtitleStyle.secondary.css') return 'secondary';
+  return null;
+}
+
+export function serializeSubtitleCssDeclarations(
+  scope: SubtitleCssScope,
+  values: Record<string, ConfigSettingsSnapshotValue | undefined>,
+): string {
+  const declarations = new Map<string, string>();
+
+  for (const declaration of LEGACY_CSS_DECLARATIONS) {
+    const path = scope === 'primary' ? declaration.primaryPath : declaration.secondaryPath;
+    const formatted = (declaration.format ?? formatCssPrimitiveValue)(values[path]);
+    if (formatted !== undefined) {
+      declarations.set(declaration.property, formatted);
+    }
+  }
+
+  const cssObject = normalizeCssDeclarationRecord(values[getSubtitleCssPath(scope)]);
+  for (const [property, value] of Object.entries(cssObject)) {
+    declarations.set(normalizeCssPropertyName(property), value);
+  }
+
+  return [...declarations.entries()]
+    .map(([property, value]) => `${property}: ${value};`)
+    .join('\n');
+}
+
+export function parseSubtitleCssDeclarations(text: string): SubtitleCssParseResult {
+  const trimmed = text.trim();
+  if (trimmed.length === 0) {
+    return { ok: true, declarations: {} };
+  }
+
+  if (/[{}]/.test(trimmed)) {
+    return {
+      ok: false,
+      error: 'Enter CSS declarations only, without selectors or braces.',
+    };
+  }
+
+  const declarations: Record<string, string> = {};
+  for (const rawDeclaration of splitCssDeclarations(trimmed)) {
+    const declaration = rawDeclaration.trim();
+    if (declaration.length === 0) continue;
+
+    const colonIndex = findTopLevelColon(declaration);
+    if (colonIndex <= 0) {
+      return { ok: false, error: `Invalid CSS declaration: ${declaration}` };
+    }
+
+    const property = normalizeCssPropertyName(declaration.slice(0, colonIndex).trim());
+    const value = declaration.slice(colonIndex + 1).trim();
+    if (!CSS_PROPERTY_PATTERN.test(property)) {
+      return { ok: false, error: `Invalid CSS property: ${property}` };
+    }
+    if (value.length === 0) {
+      return { ok: false, error: `Missing CSS value for ${property}.` };
+    }
+
+    declarations[property] = value;
+  }
+
+  return { ok: true, declarations };
+}
+
+function normalizeCssDeclarationRecord(value: unknown): Record<string, string> {
+  if (!value || typeof value !== 'object' || Array.isArray(value)) {
+    return {};
+  }
+
+  const declarations: Record<string, string> = {};
+  for (const [property, rawValue] of Object.entries(value)) {
+    if (typeof rawValue !== 'string') continue;
+    const trimmed = rawValue.trim();
+    if (trimmed.length === 0) continue;
+    declarations[property] = trimmed;
+  }
+  return declarations;
+}
+
+function normalizeCssPropertyName(property: string): string {
+  const trimmed = property.trim();
+  if (trimmed.startsWith('--')) return trimmed;
+  if (trimmed.includes('-')) return trimmed.toLowerCase();
+
+  const kebab = trimmed
+    .replace(/([a-z0-9])([A-Z])/g, '$1-$2')
+    .replace(/^Webkit-/, '-webkit-')
+    .toLowerCase();
+  return kebab.startsWith('webkit-') ? `-${kebab}` : kebab;
+}
+
+function formatCssLengthLikeValue(value: unknown): string | undefined {
+  if (typeof value === 'number' && Number.isFinite(value)) {
+    return `${value}px`;
+  }
+  return formatCssPrimitiveValue(value);
+}
+
+function formatCssPrimitiveValue(value: unknown): string | undefined {
+  if (value === null || value === undefined || typeof value === 'object') {
+    return undefined;
+  }
+
+  const text = String(value).trim();
+  return text.length > 0 ? text : undefined;
+}
+
+function splitCssDeclarations(text: string): string[] {
+  const declarations: string[] = [];
+  let current = '';
+  let quote: '"' | "'" | null = null;
+  let parenDepth = 0;
+  let escaping = false;
+
+  for (const char of text) {
+    if (escaping) {
+      current += char;
+      escaping = false;
+      continue;
+    }
+
+    if (char === '\\') {
+      current += char;
+      escaping = true;
+      continue;
+    }
+
+    if (quote) {
+      current += char;
+      if (char === quote) quote = null;
+      continue;
+    }
+
+    if (char === '"' || char === "'") {
+      current += char;
+      quote = char;
+      continue;
+    }
+
+    if (char === '(') {
+      parenDepth += 1;
+      current += char;
+      continue;
+    }
+
+    if (char === ')') {
+      parenDepth = Math.max(0, parenDepth - 1);
+      current += char;
+      continue;
+    }
+
+    if (char === ';' && parenDepth === 0) {
+      declarations.push(current);
+      current = '';
+      continue;
+    }
+
+    current += char;
+  }
+
+  declarations.push(current);
+  return declarations;
+}
+
+function findTopLevelColon(text: string): number {
+  let quote: '"' | "'" | null = null;
+  let parenDepth = 0;
+  let escaping = false;
+
+  for (let i = 0; i < text.length; i += 1) {
+    const char = text[i];
+    if (escaping) {
+      escaping = false;
+      continue;
+    }
+    if (char === '\\') {
+      escaping = true;
+      continue;
+    }
+    if (quote) {
+      if (char === quote) quote = null;
+      continue;
+    }
+    if (char === '"' || char === "'") {
+      quote = char;
+      continue;
+    }
+    if (char === '(') {
+      parenDepth += 1;
+      continue;
+    }
+    if (char === ')') {
+      parenDepth = Math.max(0, parenDepth - 1);
+      continue;
+    }
+    if (char === ':' && parenDepth === 0) {
+      return i;
+    }
+  }
+
+  return -1;
+}
diff --git a/src/types/anki.ts b/src/types/anki.ts
index e6b15b50..ba114bd0 100644
--- a/src/types/anki.ts
+++ b/src/types/anki.ts
@@ -86,6 +86,7 @@ export interface AnkiConnectConfig {
     color?: string;
   };
   nPlusOne?: {
+    enabled?: boolean;
     nPlusOne?: string;
     minSentenceWords?: number;
   };
diff --git a/src/types/config.ts b/src/types/config.ts
index 2e7a6852..808084b4 100644
--- a/src/types/config.ts
+++ b/src/types/config.ts
@@ -214,6 +214,7 @@ export interface ResolvedConfig {
       decks: Record<string, string[]>;
     };
     nPlusOne: {
+      enabled: boolean;
       minSentenceWords: number;
     };
     behavior: {
diff --git a/src/types/settings.ts b/src/types/settings.ts
index 39a2b4d4..249eb584 100644
--- a/src/types/settings.ts
+++ b/src/types/settings.ts
@@ -26,7 +26,8 @@ export type ConfigSettingsControl =
   | 'anki-note-type'
   | 'anki-field'
   | 'mpv-keybindings'
-  | 'color-list';
+  | 'color-list'
+  | 'css-declarations';
 
 export type ConfigSettingsRestartBehavior = 'hot-reload' | 'restart';
 
@@ -45,6 +46,7 @@ export interface ConfigSettingsField {
   advanced?: boolean;
   secret?: boolean;
   legacyHidden?: boolean;
+  settingsHidden?: boolean;
 }
 
 export type ConfigSettingsSnapshotValue = unknown;
diff --git a/src/types/subtitle.ts b/src/types/subtitle.ts
index a145844a..13e5c6ab 100644
--- a/src/types/subtitle.ts
+++ b/src/types/subtitle.ts
@@ -70,6 +70,7 @@ export type FrequencyDictionaryMatchMode = 'headword' | 'surface';
 
 export interface SubtitleStyleConfig {
   primaryDefaultMode?: PrimarySubMode;
+  css?: Record<string, string>;
   enableJlpt?: boolean;
   preserveLineBreaks?: boolean;
   autoPauseVideoOnHover?: boolean;
@@ -110,6 +111,7 @@ export interface SubtitleStyleConfig {
     bandedColors?: [string, string, string, string, string];
   };
   secondary?: {
+    css?: Record<string, string>;
     fontFamily?: string;
     fontSize?: number;
     fontColor?: string;