dynamic highlight color

+ refactor hooks

website/src/useTheme.jsx

@@ -0,0 +1,27 @@
+import { useState } from 'react';
+import { settings } from './repl/themes.mjs';
+import { useEffect } from 'react';
+
+function useTheme() {
+  const [theme, setTheme] = useState(localStorage.getItem('strudel-theme'));
+  useEvent('strudel-theme', (e) => setTheme(e.detail));
+  const themeSettings = settings[theme || 'strudelTheme'];
+  return {
+    theme,
+    setTheme,
+    settings: themeSettings,
+    isDark: !themeSettings.light,
+    isLight: !!themeSettings.light,
+  };
+}
+// TODO: dedupe
+function useEvent(name, onTrigger, useCapture = false) {
+  useEffect(() => {
+    document.addEventListener(name, onTrigger, useCapture);
+    return () => {
+      document.removeEventListener(name, onTrigger, useCapture);
+    };
+  }, [onTrigger]);
+}
+
+export default useTheme;