fix: preserve jlpt underline color after lookup

src/renderer/style.css

@@ -997,6 +997,31 @@ body.settings-modal-open [data-subminer-yomitan-popup-host='true'] {
   -webkit-text-fill-color: var(--subtitle-frequency-band-5-color, #8aadf4) !important;
 }
 
+#subtitleRoot .word.word-jlpt-n1::selection,
+#subtitleRoot .word.word-jlpt-n1 .c::selection {
+  text-decoration-color: var(--subtitle-jlpt-n1-color, #ed8796) !important;
+}
+
+#subtitleRoot .word.word-jlpt-n2::selection,
+#subtitleRoot .word.word-jlpt-n2 .c::selection {
+  text-decoration-color: var(--subtitle-jlpt-n2-color, #f5a97f) !important;
+}
+
+#subtitleRoot .word.word-jlpt-n3::selection,
+#subtitleRoot .word.word-jlpt-n3 .c::selection {
+  text-decoration-color: var(--subtitle-jlpt-n3-color, #f9e2af) !important;
+}
+
+#subtitleRoot .word.word-jlpt-n4::selection,
+#subtitleRoot .word.word-jlpt-n4 .c::selection {
+  text-decoration-color: var(--subtitle-jlpt-n4-color, #a6e3a1) !important;
+}
+
+#subtitleRoot .word.word-jlpt-n5::selection,
+#subtitleRoot .word.word-jlpt-n5 .c::selection {
+  text-decoration-color: var(--subtitle-jlpt-n5-color, #8aadf4) !important;
+}
+
 #subtitleRoot
   .word:is(.word-jlpt-n1, .word-jlpt-n2, .word-jlpt-n3, .word-jlpt-n4, .word-jlpt-n5):not(
     .word-known

src/renderer/subtitle-render.test.ts

@@ -1064,6 +1064,24 @@ test('subtitle annotation CSS underlines JLPT tokens without changing token colo
     /-webkit-text-fill-color:\s*var\(--subtitle-hover-token-color,\s*#f4dbd6\)\s*!important;/,
   );
 
+  for (let level = 1; level <= 5; level += 1) {
+    const jlptSelectionLockBlock = extractClassBlock(
+      cssText,
+      `#subtitleRoot .word.word-jlpt-n${level}::selection`,
+    );
+    assert.ok(
+      jlptSelectionLockBlock.length > 0,
+      `word-jlpt-n${level} selection lock should exist`,
+    );
+    assert.match(
+      jlptSelectionLockBlock,
+      new RegExp(
+        `text-decoration-color:\\s*var\\(--subtitle-jlpt-n${level}-color,\\s*#[0-9a-f]{6}\\)\\s*!important;`,
+        'i',
+      ),
+    );
+  }
+
   const selectionBlock = extractClassBlock(cssText, '#subtitleRoot::selection');
   assert.match(
     selectionBlock,