More theme stuff

src-web/hooks/usePreferredAppearance.ts

@@ -0,0 +1,18 @@
+import { useEffect, useState } from 'react';
+import {
+  type Appearance,
+  getPreferredAppearance,
+  subscribeToPreferredAppearanceChange,
+} from '../lib/theme/window';
+
+export function usePreferredAppearance() {
+  const [preferredAppearance, setPreferredAppearance] = useState<Appearance>();
+
+  // Set appearance when preferred theme changes
+  useEffect(() => {
+    getPreferredAppearance().then(setPreferredAppearance);
+    return subscribeToPreferredAppearanceChange(setPreferredAppearance);
+  }, []);
+
+  return preferredAppearance;
+}