diff --git a/src/services/theme.service.ts b/src/services/theme.service.ts
index c363f2e..1a3c2ad 100644
--- a/src/services/theme.service.ts
+++ b/src/services/theme.service.ts
@@ -4,80 +4,89 @@
  * Single Responsibility: Orchestrate theme business logic.
  *
  * This service is the ONLY layer that knows about both storage and DOM.
- * It delegates:
- *   - Persistence  → theme.storage.ts
- *   - DOM mutation → applyTheme.ts (utils)
- *
- * FUTURE API INTEGRATION:
- *   When a backend API is introduced, only this file changes.
- *   The storage layer, DOM utility, context, and hook remain untouched.
- *   Pattern: replace loadTheme() / saveTheme() calls with API calls,
- *   keeping the same method signatures.
- *
- * RULES:
- *   - No React imports.
- *   - No JSX.
- *   - No component access.
+ * It delegates persistence to the backend database via REST API.
  */
 
 import type { Theme } from "../types/theme.types";
-import {
-  loadTheme as storageLoad,
-  saveTheme as storageSave,
-  clearTheme as storageClear,
-} from "../storage/theme.storage";
+import apiClient from "../api/axiosInstance";
 import { applyTheme as applyThemeToDom } from "../utils/applyTheme";
 import { DEFAULT_THEME, AVAILABLE_THEMES } from "../constants/themes";
 
 export { DEFAULT_THEME, AVAILABLE_THEMES };
 
+let currentTheme: Theme = DEFAULT_THEME;
+
+// Load user theme preference asynchronously during application initialization (module import)
+try {
+  const token = localStorage.getItem("accessToken");
+  if (token) {
+    const response = await apiClient.get<{ success: boolean; data: { themeCode: string } }>("/api/v1/settings/theme");
+    if (response && response.success && response.data?.themeCode) {
+      const themeCode = response.data.themeCode;
+      const found = AVAILABLE_THEMES.find((t) => t.id === themeCode);
+      if (found) {
+        currentTheme = found;
+      }
+    }
+  }
+} catch (error) {
+  console.error("Failed to load user theme preference asynchronously at startup:", error);
+}
+
+// Apply the resolved theme to the DOM immediately prior to React tree mount
+applyThemeToDom(currentTheme.palette);
+if (typeof document !== "undefined") {
+  if (currentTheme.mode === "dark") {
+    document.documentElement.classList.add("dark");
+  } else {
+    document.documentElement.classList.remove("dark");
+  }
+}
+
 // ─────────────────────────────────────────────────────────────────────────────
 // PUBLIC SERVICE METHODS
 // ─────────────────────────────────────────────────────────────────────────────
 
 /**
- * Returns the currently persisted theme from storage.
- * Falls back to DEFAULT_THEME if nothing is saved or storage fails.
+ * Returns the loaded theme.
  */
 export function getCurrentTheme(): Theme {
-  const saved = storageLoad();
-  if (!saved) return DEFAULT_THEME;
-  // If the saved theme id still exists in the registry, use it.
-  // Otherwise (e.g. default changed), fall back to DEFAULT_THEME.
-  const exists = AVAILABLE_THEMES.some((t) => t.id === saved.id);
-  return exists ? saved : DEFAULT_THEME;
+  return currentTheme;
 }
 
 /**
  * Returns all themes available for selection.
- * Future: merge with API-fetched tenant themes.
  */
 export function getAvailableThemes(): Theme[] {
   return AVAILABLE_THEMES;
 }
 
 /**
- * Persists a theme to storage.
- * Does NOT apply it to the DOM — call applyTheme() separately if needed.
+ * Persists a theme to the backend database.
  *
  * @param theme - The theme to persist.
  */
 export function saveTheme(theme: Theme): void {
-  storageSave(theme);
+  currentTheme = theme;
+  const themeCode = (theme as any).code || theme.id;
+  apiClient.put("/api/v1/settings/theme", { themeCode })
+    .catch((err) => {
+      console.error("Failed to save theme preference to DB:", err);
+    });
 }
 
 /**
- * Resets to the default theme:
- *   1. Clears persisted theme from storage.
- *   2. Removes all runtime CSS variable overrides from the DOM.
- *      The static @theme values in index.css take effect again.
+ * Resets to the default theme.
  *
  * @returns The default theme, so the caller can update its state.
  */
 export function resetTheme(): Theme {
-  storageClear();
-  // Apply explicitly so the DOM reflects DEFAULT_THEME (Royal Purple),
-  // matching the static @theme values in index.css.
+  currentTheme = DEFAULT_THEME;
+  apiClient.put("/api/v1/settings/theme", { themeCode: DEFAULT_THEME.id })
+    .catch((err) => {
+      console.error("Failed to reset theme preference on DB:", err);
+    });
+
   applyThemeToDom(DEFAULT_THEME.palette);
   if (typeof document !== "undefined") {
     document.documentElement.classList.remove("dark");