Dark/light mode added + switcher

frontend/src/utils/theme.js

@@ -0,0 +1,30 @@
+const LIGHT = "latte";
+const DARK = "macchiato";
+
+export function getSystemTheme() {
+    return window.matchMedia("(prefers-color-scheme: dark)").matches
+        ? DARK
+        : LIGHT;
+}
+
+export function getStoredTheme() {
+    return localStorage.getItem("theme");
+}
+
+export function getInitialTheme() {
+    return getStoredTheme() || getSystemTheme();
+}
+
+export function applyTheme(theme) {
+    const root = document.documentElement;
+
+    root.classList.remove(LIGHT, DARK);
+
+    root.classList.add(theme);
+
+    localStorage.setItem("theme", theme);
+}
+
+export function toggleTheme(current) {
+    return current === DARK ? LIGHT : DARK;
+}