feat: theme switcher

src/util.ts

@@ -59,3 +59,7 @@ export const hasFeature = (pkg: Package | undefined, feature: Feature) => {
 export const messageSplit = (message: any) => {
     return message.message?.split('\n');
 };
+
+export const shouldPreferDark = () => {
+    return window.matchMedia('(prefers-color-scheme: dark)').matches;
+};