diff --git a/src/features/editor/ui/HighlightButton.tsx b/src/features/editor/ui/HighlightButton.tsx
index a305b36..e7dca88 100644
--- a/src/features/editor/ui/HighlightButton.tsx
+++ b/src/features/editor/ui/HighlightButton.tsx
@@ -7,13 +7,16 @@ import { Highlighter } from 'lucide-react'
 import { useCallback } from 'react'
 
 /**
- * Yellow highlight color value used for the highlight style.
+ * Unique identifier for the highlighter style.
+ * Uses a dedicated value ("highlight") instead of BlockNote's built-in
+ * colour names so that the highlighter and the color-picker's yellow
+ * are treated as separate styles.
  */
-const HIGHLIGHT_COLOR = 'yellow'
+const HIGHLIGHT_STYLE = 'highlight'
 
 /**
- * Toggle button that applies or removes a yellow highlight on the
- * selected text using BlockNote's built-in `backgroundColor` style.
+ * Toggle button that applies or removes a fluorescent-yellow highlight
+ * on the selected text using a custom `backgroundColor` style value.
  *
  * The button is hidden when the editor is read-only or no inline
  * content is selected.  It appears active (pressed) when the
@@ -26,13 +29,17 @@ export const HighlightButton = () => {
   const state = useEditorState({
     editor,
     selector: ({ editor }) => {
+      // Hide the button when the editor is in read-only mode.
       if (!editor.isEditable) {
         return undefined
       }
 
+      // Collect the blocks covered by the current selection (or the block at cursor).
       const selectedBlocks = editor.getSelection()?.blocks || [
         editor.getTextCursorPosition().block,
       ]
+
+      // Hide the button when none of the selected blocks contain inline content.
       const hasContent = selectedBlocks.some(
         (block) => block.content !== undefined
       )
@@ -40,24 +47,30 @@ export const HighlightButton = () => {
         return undefined
       }
 
+      // Determine whether the highlight style is already applied to the selection.
       const activeBg = editor.getActiveStyles().backgroundColor
-      return { active: activeBg === HIGHLIGHT_COLOR }
+      return { active: activeBg === HIGHLIGHT_STYLE }
     },
   })
 
+  /**
+   * Toggles the fluorescent highlight on the current editor selection.
+   *
+   * Focuses the editor first, then adds or removes the custom
+   * `backgroundColor: "highlight"` style depending on whether the
+   * highlight is already active on the selection.
+   */
   const toggleHighlight = useCallback(() => {
     editor.focus()
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
-    const style = { backgroundColor: HIGHLIGHT_COLOR } as any
-    const isHighlighted =
-      editor.getActiveStyles().backgroundColor === HIGHLIGHT_COLOR
+    const style = { backgroundColor: HIGHLIGHT_STYLE } as any
 
-    if (isHighlighted) {
+    if (state?.active) {
       editor.removeStyles(style)
     } else {
       editor.addStyles(style)
     }
-  }, [editor])
+  }, [editor, state])
 
   if (state === undefined) {
     return null
diff --git a/src/index.css b/src/index.css
index 23adffc..dbe3ffc 100644
--- a/src/index.css
+++ b/src/index.css
@@ -240,6 +240,19 @@ body {
   color: oklch(0.828 0.111 54);
 }
 
+/*
+ * Highlighter markers – shared shape.
+ *
+ * Both "yellow" (colour-picker) and "highlight" (dedicated highlighter) use
+ * the same padding / margin / border-radius to emulate a highlighter stroke.
+ */
+span[data-style-type="backgroundColor"][data-value="yellow"],
+span[data-style-type="backgroundColor"][data-value="highlight"] {
+  padding: 0.1em 0.15em;
+  margin-right: 0.1em;
+  border-radius: 0.2em;
+}
+
 /*
  * Highlighter marker (yellow) - light mode.
  *
@@ -249,9 +262,6 @@ body {
  */
 span[data-style-type="backgroundColor"][data-value="yellow"] {
   background-color: oklch(0.92 0.17 90);
-  padding: 0.1em 0.15em;
-  margin-right: 0.1em;
-  border-radius: 0.2em;
 }
 
 /*
@@ -265,6 +275,24 @@ span[data-style-type="backgroundColor"][data-value="yellow"] {
   color: oklch(0.25 0.05 85);
 }
 
+/*
+ * Highlighter marker (fluorescent) - light mode.
+ *
+ * Dedicated highlighter style that is independent from the colour
+ * picker's "yellow" so the two can use different shades.
+ */
+span[data-style-type="backgroundColor"][data-value="highlight"] {
+  background-color: oklch(0.96 0.11 95);
+}
+
+/*
+ * Highlighter marker (fluorescent) - dark mode.
+ */
+.dark span[data-style-type="backgroundColor"][data-value="highlight"] {
+  background-color: oklch(0.75 0.10 95);
+  color: oklch(0.25 0.05 85);
+}
+
 /*
  * Override BlockNote link colour in dark mode.
  *
@@ -496,28 +524,39 @@ html.cursor-autohide-hidden * {
   cursor: none !important;
 }
 
-html.cursor-autohide-hidden [role="dialog"],
-html.cursor-autohide-hidden [role="menu"],
-html.cursor-autohide-hidden [role="listbox"],
-html.cursor-autohide-hidden .bn-suggestion-menu,
-html.cursor-autohide-hidden .bn-link-toolbar,
-html.cursor-autohide-hidden .bn-color-picker-dropdown,
-html.cursor-autohide-hidden .bn-formatting-toolbar,
-html.cursor-autohide-hidden .bn-table-handle-menu,
-html.cursor-autohide-hidden [data-slot="select-content"],
-html.cursor-autohide-hidden [data-slot="dropdown-menu-content"] {
+/*
+ * Interactive overlays that keep the cursor visible during auto-hide.
+ *
+ * The `:is()` pseudo-class avoids repeating the `html.cursor-autohide-hidden`
+ * ancestor for every selector.  The first rule targets the overlay containers
+ * themselves; the second targets their descendants.
+ */
+html.cursor-autohide-hidden :is(
+  [role="dialog"],
+  [role="menu"],
+  [role="listbox"],
+  .bn-suggestion-menu,
+  .bn-link-toolbar,
+  .bn-color-picker-dropdown,
+  .bn-formatting-toolbar,
+  .bn-table-handle-menu,
+  [data-slot="select-content"],
+  [data-slot="dropdown-menu-content"]
+) {
   cursor: auto !important;
 }
 
-html.cursor-autohide-hidden [role="dialog"] *,
-html.cursor-autohide-hidden [role="menu"] *,
-html.cursor-autohide-hidden [role="listbox"] *,
-html.cursor-autohide-hidden .bn-suggestion-menu *,
-html.cursor-autohide-hidden .bn-link-toolbar *,
-html.cursor-autohide-hidden .bn-color-picker-dropdown *,
-html.cursor-autohide-hidden .bn-formatting-toolbar *,
-html.cursor-autohide-hidden .bn-table-handle-menu *,
-html.cursor-autohide-hidden [data-slot="select-content"] *,
-html.cursor-autohide-hidden [data-slot="dropdown-menu-content"] * {
+html.cursor-autohide-hidden :is(
+  [role="dialog"],
+  [role="menu"],
+  [role="listbox"],
+  .bn-suggestion-menu,
+  .bn-link-toolbar,
+  .bn-color-picker-dropdown,
+  .bn-formatting-toolbar,
+  .bn-table-handle-menu,
+  [data-slot="select-content"],
+  [data-slot="dropdown-menu-content"]
+) * {
   cursor: auto !important;
 }