diff --git a/frontend/package-lock.json b/frontend/package-lock.json
index 04614e4..949b301 100644
--- a/frontend/package-lock.json
+++ b/frontend/package-lock.json
@@ -1838,6 +1838,14 @@
         "@types/react": "^19.2.0"
       }
     },
+    "node_modules/@types/trusted-types": {
+      "version": "2.0.7",
+      "resolved": "https://registry.npmjs.org/@types/trusted-types/-/trusted-types-2.0.7.tgz",
+      "integrity": "sha512-ScaPdn1dQczgbl0QFTeTOmVHFULt394XJgOQNoyVhZ6r2vLnMLJfBPd53SB52T/3G36VI1/g2MZaX0cwDuXsfw==",
+      "license": "MIT",
+      "optional": true,
+      "peer": true
+    },
     "node_modules/@typescript-eslint/eslint-plugin": {
       "version": "8.56.1",
       "resolved": "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-8.56.1.tgz",
diff --git a/frontend/src/App.css b/frontend/src/App.css
index 5c3423a..0cc2e43 100644
--- a/frontend/src/App.css
+++ b/frontend/src/App.css
@@ -181,11 +181,70 @@ body {
     width: 100% !important;
     min-width: unset;
     max-width: unset;
+    flex: 1;
   }
 
   .resize-handle {
-    width: 100%;
-    height: 5px;
-    cursor: row-resize;
+    display: none;
+  }
+}
+
+/* ── Mobile tab bar ──────────────────────────────── */
+.mobile-tab-bar {
+  display: none;
+}
+
+@media (max-width: 768px) {
+  .mobile-tab-bar {
+    display: flex;
+    flex-shrink: 0;
+    height: 54px;
+    background: #252526;
+    border-top: 1px solid #007acc;
+    z-index: 50;
+  }
+
+  .mobile-tab-btn {
+    flex: 1;
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    gap: 3px;
+    background: transparent;
+    border: none;
+    color: #7a7a7a;
+    font-size: 11px;
+    font-weight: 500;
+    cursor: pointer;
+    transition: color 0.15s, background 0.15s;
+    padding: 6px 0;
+  }
+
+  .mobile-tab-btn--active {
+    color: #007acc;
+    background: rgba(0, 122, 204, 0.08);
+  }
+
+  .mobile-tab-btn:active {
+    background: rgba(255, 255, 255, 0.06);
+  }
+}
+
+/* ── Header responsive ───────────────────────────── */
+@media (max-width: 768px) {
+  .app-header {
+    padding: 0 10px;
+    height: 44px;
+  }
+
+  .examples-link span,
+  .header-github-text,
+  .header-username-text {
+    display: none;
+  }
+
+  .examples-link {
+    padding: 6px 8px;
   }
 }
diff --git a/frontend/src/components/layout/AppHeader.tsx b/frontend/src/components/layout/AppHeader.tsx
index 360717e..4213036 100644
--- a/frontend/src/components/layout/AppHeader.tsx
+++ b/frontend/src/components/layout/AppHeader.tsx
@@ -47,7 +47,7 @@ export const AppHeader: React.FC<AppHeaderProps> = () => {
             <path d="M2 3h6a4 4 0 0 1 4 4v14a3 3 0 0 0-3-3H2z" />
             <path d="M22 3h-6a4 4 0 0 0-4 4v14a3 3 0 0 1 3-3h7z" />
           </svg>
-          Examples
+          <span>Examples</span>
         </Link>
 
         <a
@@ -60,7 +60,7 @@ export const AppHeader: React.FC<AppHeaderProps> = () => {
           <svg width="16" height="16" viewBox="0 0 24 24" fill="currentColor">
             <path d="M12 2C6.477 2 2 6.484 2 12.021c0 4.428 2.865 8.185 6.839 9.504.5.092.682-.217.682-.482 0-.237-.009-.868-.013-1.703-2.782.605-3.369-1.342-3.369-1.342-.454-1.154-1.11-1.462-1.11-1.462-.908-.62.069-.608.069-.608 1.003.07 1.531 1.032 1.531 1.032.892 1.53 2.341 1.088 2.91.832.092-.647.35-1.088.636-1.338-2.22-.253-4.555-1.113-4.555-4.951 0-1.093.39-1.988 1.029-2.688-.103-.253-.446-1.272.098-2.65 0 0 .84-.27 2.75 1.026A9.564 9.564 0 0 1 12 6.844a9.59 9.59 0 0 1 2.504.337c1.909-1.296 2.747-1.026 2.747-1.026.546 1.378.202 2.397.1 2.65.64.7 1.028 1.595 1.028 2.688 0 3.848-2.338 4.695-4.566 4.944.359.309.678.919.678 1.852 0 1.336-.012 2.415-.012 2.743 0 .267.18.578.688.48C19.138 20.203 22 16.447 22 12.021 22 6.484 17.523 2 12 2z" />
           </svg>
-          GitHub
+          <span className="header-github-text">GitHub</span>
         </a>
 
         {/* Auth UI */}
@@ -77,7 +77,7 @@ export const AppHeader: React.FC<AppHeaderProps> = () => {
                   {user.username[0].toUpperCase()}
                 </div>
               )}
-              {user.username}
+              <span className="header-username-text">{user.username}</span>
             </button>
 
             {dropdownOpen && (
diff --git a/frontend/src/pages/EditorPage.tsx b/frontend/src/pages/EditorPage.tsx
index 398b025..7e2b344 100644
--- a/frontend/src/pages/EditorPage.tsx
+++ b/frontend/src/pages/EditorPage.tsx
@@ -18,6 +18,8 @@ import { useAuthStore } from '../store/useAuthStore';
 import type { CompilationLog } from '../utils/compilationLogger';
 import '../App.css';
 
+const MOBILE_BREAKPOINT = 768;
+
 const BOTTOM_PANEL_MIN = 80;
 const BOTTOM_PANEL_MAX = 600;
 const BOTTOM_PANEL_DEFAULT = 200;
@@ -47,6 +49,9 @@ export const EditorPage: React.FC = () => {
   const [loginPromptOpen, setLoginPromptOpen] = useState(false);
   const [explorerOpen, setExplorerOpen] = useState(true);
   const [explorerWidth, setExplorerWidth] = useState(EXPLORER_DEFAULT);
+  const [isMobile, setIsMobile] = useState(() => window.matchMedia(`(max-width: ${MOBILE_BREAKPOINT}px)`).matches);
+  // Default to 'circuit' on mobile — the visual simulation is the primary content
+  const [mobileView, setMobileView] = useState<'code' | 'circuit'>('circuit');
   const user = useAuthStore((s) => s.user);
 
   const handleSaveClick = useCallback(() => {
@@ -57,6 +62,19 @@ export const EditorPage: React.FC = () => {
     }
   }, [user]);
 
+  // Track mobile breakpoint
+  useEffect(() => {
+    const mq = window.matchMedia(`(max-width: ${MOBILE_BREAKPOINT}px)`);
+    const update = (e: MediaQueryListEvent | MediaQueryList) => {
+      const mobile = e.matches;
+      setIsMobile(mobile);
+      if (mobile) setExplorerOpen(false);
+    };
+    update(mq);
+    mq.addEventListener('change', update);
+    return () => mq.removeEventListener('change', update);
+  }, []);
+
   // Ctrl+S shortcut
   useEffect(() => {
     const handler = (e: KeyboardEvent) => {
@@ -157,7 +175,11 @@ export const EditorPage: React.FC = () => {
         {/* ── Editor side ── */}
         <div
           className="editor-panel"
-          style={{ width: `${editorWidthPct}%`, display: 'flex', flexDirection: 'row' }}
+          style={{
+            width: isMobile ? '100%' : `${editorWidthPct}%`,
+            display: isMobile && mobileView !== 'code' ? 'none' : 'flex',
+            flexDirection: 'row',
+          }}
         >
           {/* File explorer sidebar + resize handle */}
           {explorerOpen && (
@@ -165,7 +187,9 @@ export const EditorPage: React.FC = () => {
               <div style={{ width: explorerWidth, flexShrink: 0, display: 'flex', overflow: 'hidden' }}>
                 <FileExplorer onSaveClick={handleSaveClick} />
               </div>
-              <div className="explorer-resize-handle" onMouseDown={handleExplorerResizeMouseDown} />
+              {!isMobile && (
+                <div className="explorer-resize-handle" onMouseDown={handleExplorerResizeMouseDown} />
+              )}
             </>
           )}
 
@@ -221,15 +245,21 @@ export const EditorPage: React.FC = () => {
           </div>
         </div>
 
-        {/* Resize handle */}
-        <div className="resize-handle" onMouseDown={handleResizeMouseDown}>
-          <div className="resize-handle-grip" />
-        </div>
+        {/* Resize handle (desktop only) */}
+        {!isMobile && (
+          <div className="resize-handle" onMouseDown={handleResizeMouseDown}>
+            <div className="resize-handle-grip" />
+          </div>
+        )}
 
         {/* ── Simulator side ── */}
         <div
           className="simulator-panel"
-          style={{ width: `${100 - editorWidthPct}%`, display: 'flex', flexDirection: 'column' }}
+          style={{
+            width: isMobile ? '100%' : `${100 - editorWidthPct}%`,
+            display: isMobile && mobileView !== 'circuit' ? 'none' : 'flex',
+            flexDirection: 'column',
+          }}
         >
           <div style={{ flex: 1, overflow: 'hidden', position: 'relative', minHeight: 0 }}>
             <SimulatorCanvas />
@@ -249,6 +279,34 @@ export const EditorPage: React.FC = () => {
         </div>
       </div>
 
+      {/* ── Mobile tab bar ── */}
+      {isMobile && (
+        <nav className="mobile-tab-bar">
+          <button
+            className={`mobile-tab-btn${mobileView === 'code' ? ' mobile-tab-btn--active' : ''}`}
+            onClick={() => setMobileView('code')}
+          >
+            <svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
+              <polyline points="16 18 22 12 16 6" />
+              <polyline points="8 6 2 12 8 18" />
+            </svg>
+            <span>Code</span>
+          </button>
+          <button
+            className={`mobile-tab-btn${mobileView === 'circuit' ? ' mobile-tab-btn--active' : ''}`}
+            onClick={() => setMobileView('circuit')}
+          >
+            <svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
+              <rect x="2" y="7" width="20" height="14" rx="2" />
+              <path d="M16 7V5a2 2 0 0 0-2-2h-4a2 2 0 0 0-2 2v2" />
+              <line x1="12" y1="12" x2="12" y2="16" />
+              <line x1="10" y1="14" x2="14" y2="14" />
+            </svg>
+            <span>Circuit</span>
+          </button>
+        </nav>
+      )}
+
       {saveModalOpen && <SaveProjectModal onClose={() => setSaveModalOpen(false)} />}
       {loginPromptOpen && <LoginPromptModal onClose={() => setLoginPromptOpen(false)} />}
     </div>