add themes, home component, body css

src/hooks/use-theme.ts

@@ -0,0 +1,21 @@
+import { create, StoreApi } from 'zustand';
+
+interface ThemeState {
+  theme: string;
+  setTheme: (theme: string) => void;
+}
+
+const useThemeStore = create<ThemeState>((set: StoreApi<ThemeState>['setState']) => ({
+  theme: localStorage.getItem('theme') || 'yotsuba',
+  setTheme: (theme: string) => {
+    localStorage.setItem('theme', theme);
+    set({ theme });
+  },
+}));
+
+const useTheme = (): [string, (theme: string) => void] => {
+  const { theme, setTheme } = useThemeStore();
+  return [theme, setTheme];
+};
+
+export default useTheme;