feat(editor): block comment extension (#12980)

#### PR Dependency Tree


* **PR #12980** 👈

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blocksuite/affine/blocks/bookmark/src/styles.ts

@@ -1,4 +1,4 @@
-import { unsafeCSSVar } from '@blocksuite/affine-shared/theme';
+import { unsafeCSSVar, unsafeCSSVarV2 } from '@blocksuite/affine-shared/theme';
 import { baseTheme } from '@toeverything/theme';
 import { css, unsafeCSS } from 'lit';
 
@@ -158,6 +158,10 @@ export const styles = css`
     border-radius: 4px;
   }
 
+  .affine-bookmark-card.comment-highlighted {
+    outline: 2px solid ${unsafeCSSVarV2('block/comment/highlightUnderline')};
+  }
+
   .affine-bookmark-card.loading {
     .affine-bookmark-content-title-text {
       color: var(--affine-placeholder-color);