diff --git a/frontend/src/App.jsx b/frontend/src/App.jsx
index 40b24d7..872f868 100644
--- a/frontend/src/App.jsx
+++ b/frontend/src/App.jsx
@@ -54,6 +54,36 @@ export default function App() {
   const tmDragY0 = useRef(0)
   const tmDragH0 = useRef(0)
 
+  // Focus mode — collapses sidebar, bundles nav, terminal for distraction-free reading
+  const [focusMode, setFocusMode] = useState(false)
+  const focusSavedState = useRef(null)
+
+  const toggleFocusMode = useCallback(() => {
+    if (!focusMode) {
+      // Save current states then collapse everything
+      focusSavedState.current = { sidebarCollapsed, bundlesCollapsed, termCollapsed }
+      setSidebarCollapsed(true)
+      setBundlesCollapsed(true)
+      setTermCollapsed(true)
+      setFocusMode(true)
+    } else {
+      // Restore previous states
+      const saved = focusSavedState.current || {}
+      setSidebarCollapsed(saved.sidebarCollapsed ?? false)
+      setBundlesCollapsed(saved.bundlesCollapsed ?? false)
+      setTermCollapsed(saved.termCollapsed ?? false)
+      setFocusMode(false)
+    }
+  }, [focusMode, sidebarCollapsed, bundlesCollapsed, termCollapsed])
+
+  // If the user manually opens any panel while in focus mode, exit focus mode
+  // so the button icon reverts to "expand" (next click re-collapses everything)
+  useEffect(() => {
+    if (focusMode && (!sidebarCollapsed || !bundlesCollapsed || !termCollapsed)) {
+      setFocusMode(false)
+    }
+  }, [sidebarCollapsed, bundlesCollapsed, termCollapsed, focusMode])
+
   // Track previous scenario id to teardown on switch
   const prevActiveIdRef = useRef(null)
 
@@ -330,6 +360,8 @@ export default function App() {
               isExamMode={!!examSession}
               examProgress={examProgress}
               totalExamWeight={totalExamWeight}
+              focusMode={focusMode}
+              onToggleFocus={toggleFocusMode}
             />
           </div>
 
diff --git a/frontend/src/components/ScenarioPanel.jsx b/frontend/src/components/ScenarioPanel.jsx
index 61ef502..8b189f5 100644
--- a/frontend/src/components/ScenarioPanel.jsx
+++ b/frontend/src/components/ScenarioPanel.jsx
@@ -24,7 +24,7 @@ async function resetProgress(scope, opts) {
   })
 }
 
-export default function ScenarioPanel({ scenario, onProgressUpdate, onScenarioStart, isExamMode, examProgress, totalExamWeight }) {
+export default function ScenarioPanel({ scenario, onProgressUpdate, onScenarioStart, isExamMode, examProgress, totalExamWeight, focusMode, onToggleFocus }) {
   const [tab, setTab] = useState('problem')
   const [setupState, setSetupState] = useState('idle') // idle | running | done | error
   const [validating, setValidating] = useState(false)
@@ -216,6 +216,29 @@ export default function ScenarioPanel({ scenario, onProgressUpdate, onScenarioSt
         </div>
         <div className={styles.titleRow}>
           <div className={styles.scenarioTitle}>{scenario.title}</div>
+          {onToggleFocus && !isExamMode && (
+            <button
+              className={focusMode ? styles.focusBtnActive : styles.focusBtn}
+              onClick={onToggleFocus}
+              title={focusMode ? 'Exit focus mode' : 'Focus mode — hide sidebar, terminal & nav'}
+            >
+              {focusMode ? (
+                <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2.5" strokeLinecap="round" strokeLinejoin="round">
+                  <polyline points="4 14 10 14 10 20" />
+                  <polyline points="20 10 14 10 14 4" />
+                  <line x1="10" y1="14" x2="3" y2="21" />
+                  <line x1="21" y1="3" x2="14" y2="10" />
+                </svg>
+              ) : (
+                <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2.5" strokeLinecap="round" strokeLinejoin="round">
+                  <polyline points="15 3 21 3 21 9" />
+                  <polyline points="9 21 3 21 3 15" />
+                  <line x1="21" y1="3" x2="14" y2="10" />
+                  <line x1="3" y1="21" x2="10" y2="14" />
+                </svg>
+              )}
+            </button>
+          )}
           {isExamMode && scenario.progress?.started_at && (
             <div className={styles.progressStats}>
               <div className={styles.statItem}>
@@ -238,6 +261,29 @@ export default function ScenarioPanel({ scenario, onProgressUpdate, onScenarioSt
               </div>
             </div>
           )}
+          {onToggleFocus && isExamMode && (
+            <button
+              className={focusMode ? styles.focusBtnActive : styles.focusBtn}
+              onClick={onToggleFocus}
+              title={focusMode ? 'Exit focus mode' : 'Focus mode — hide sidebar, terminal & nav'}
+            >
+              {focusMode ? (
+                <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2.5" strokeLinecap="round" strokeLinejoin="round">
+                  <polyline points="4 14 10 14 10 20" />
+                  <polyline points="20 10 14 10 14 4" />
+                  <line x1="10" y1="14" x2="3" y2="21" />
+                  <line x1="21" y1="3" x2="14" y2="10" />
+                </svg>
+              ) : (
+                <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2.5" strokeLinecap="round" strokeLinejoin="round">
+                  <polyline points="15 3 21 3 21 9" />
+                  <polyline points="9 21 3 21 3 15" />
+                  <line x1="21" y1="3" x2="14" y2="10" />
+                  <line x1="3" y1="21" x2="10" y2="14" />
+                </svg>
+              )}
+            </button>
+          )}
           {scenario.progress?.status !== 'not_started' && scenario.progress?.attempts > 0 && (
             <button
               className={styles.resetBtn}
diff --git a/frontend/src/components/ScenarioPanel.module.css b/frontend/src/components/ScenarioPanel.module.css
index b55dfeb..45ddbd6 100644
--- a/frontend/src/components/ScenarioPanel.module.css
+++ b/frontend/src/components/ScenarioPanel.module.css
@@ -128,6 +128,34 @@
   background: var(--red-dim);
 }
 
+.focusBtn {
+  flex-shrink: 0;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  background: var(--surface2);
+  border: 1px solid var(--border2);
+  border-radius: 6px;
+  color: var(--text-3);
+  width: 28px;
+  height: 28px;
+  cursor: pointer;
+  align-self: center;
+  transition: color 0.12s, border-color 0.12s, background 0.12s;
+}
+.focusBtn:hover {
+  color: var(--green);
+  border-color: color-mix(in srgb, var(--green) 40%, transparent);
+  background: var(--green-dim);
+}
+.focusBtnActive {
+  composes: focusBtn;
+  color: var(--green);
+  border-color: color-mix(in srgb, var(--green) 40%, transparent);
+  background: var(--green-dim);
+}
+
+
 .completedBanner {
   margin-top: 8px;
   font-size: 12px;