redesign the homepage

apps/homepage/src/lib/theme/client.ts

@@ -0,0 +1,44 @@
+import {
+  isThemePreference,
+  resolveTheme,
+  themeCookie,
+  themeCookieMaxAgeSeconds,
+  themeStorageKey,
+  type ThemePreference,
+} from './config';
+
+export const themePreferenceEvent = 'rentaldrivego:theme-preference';
+
+export function applyTheme(preference: ThemePreference): void {
+  const systemDark = window.matchMedia('(prefers-color-scheme: dark)').matches;
+  const resolved = resolveTheme(preference, systemDark);
+  const root = document.documentElement;
+  root.dataset.themePreference = preference;
+  root.dataset.theme = resolved;
+}
+
+export function persistTheme(preference: ThemePreference): void {
+  try {
+    window.localStorage.setItem(themeStorageKey, preference);
+  } catch {
+    // Storage can be unavailable; the first-party cookie remains canonical.
+  }
+
+  const secure = window.location.protocol === 'https:' ? '; Secure' : '';
+  document.cookie =
+    [
+      `${themeCookie}=${encodeURIComponent(preference)}`,
+      'Path=/',
+      `Max-Age=${themeCookieMaxAgeSeconds}`,
+      'SameSite=Lax',
+    ].join('; ') + secure;
+  applyTheme(preference);
+  window.dispatchEvent(
+    new CustomEvent<ThemePreference>(themePreferenceEvent, { detail: preference }),
+  );
+}
+
+export function currentThemePreference(): ThemePreference {
+  const value = document.documentElement.dataset.themePreference;
+  return isThemePreference(value) ? value : 'system';
+}