diff --git a/apps/web/index.html b/apps/web/index.html
index 3b0727772..67efc12ae 100644
--- a/apps/web/index.html
+++ b/apps/web/index.html
@@ -7,6 +7,16 @@
       name="description"
       content="Corbits Workbench: deploy, run, and supervise agents from one interface."
     />
+    <script>
+      // Paint in the saved theme before React mounts; theme-store.ts writes the key.
+      try {
+        var t = localStorage.getItem("corbits-theme:last");
+        var r = document.documentElement;
+        if (t === "dark" || t === "canvas") r.setAttribute("data-theme", t);
+        if (t === "dark") r.classList.add("dark");
+        r.style.colorScheme = t === "dark" ? "dark" : "light";
+      } catch (e) {}
+    </script>
     <title>Corbits Workbench</title>
     <link rel="icon" type="image/svg+xml" href="/corbits-favicon.svg" />
     <link rel="preconnect" href="https://fonts.googleapis.com" />
diff --git a/apps/web/src/theme-store.ts b/apps/web/src/theme-store.ts
index 63663f84b..0bf67a111 100644
--- a/apps/web/src/theme-store.ts
+++ b/apps/web/src/theme-store.ts
@@ -12,6 +12,8 @@ export function isTheme(value: unknown): value is Theme {
 }
 
 const DEFAULT_KEY = "corbits-theme";
+// Unscoped copy of the last-set theme; the boot script in index.html reads it.
+const LAST_KEY = "corbits-theme:last";
 
 let storageKey = DEFAULT_KEY;
 let current: Theme = "light";
@@ -33,6 +35,7 @@ function apply(theme: Theme) {
   else root.setAttribute("data-theme", theme);
   // react-ui's `dark:` variant keys off the class.
   root.classList.toggle("dark", theme === "dark");
+  root.style.colorScheme = theme === "dark" ? "dark" : "light";
 }
 
 function commit(theme: Theme) {
@@ -53,6 +56,7 @@ export function setTheme(theme: Theme) {
   commit(theme);
   try {
     window.localStorage.setItem(storageKey, theme);
+    window.localStorage.setItem(LAST_KEY, theme);
   } catch (error) {
     reportError(error, { operation: "theme_persist" });
   }