diff --git a/resources/js/candidate-proctor.js b/resources/js/candidate-proctor.js
index 67d1aac..a418df7 100644
--- a/resources/js/candidate-proctor.js
+++ b/resources/js/candidate-proctor.js
@@ -343,6 +343,70 @@ export function uploadTabScreenshotBlob(imageData, reason = 'tab_switch') {
     .catch(err => console.log('System screenshot fetch error:', err));
 }
 
+export function isEntireScreenShare(track) {
+    if (!track || !track.getSettings) return true;
+    const settings = track.getSettings();
+    const surface = settings.displaySurface;
+
+    if (surface) {
+        const allowedSurfaces = ['monitor', 'screen'];
+        if (!allowedSurfaces.includes(surface)) {
+            return false;
+        }
+    }
+
+    if (window.screen && window.screen.width && settings.width) {
+        if (settings.width < (window.screen.width * 0.65) && settings.height < (window.screen.height * 0.65)) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+export function isScreenSharingActive() {
+    return Boolean(screenShareStream && screenShareStream.active && screenShareStream.getVideoTracks().some(t => t.readyState === 'live'));
+}
+
+export function enforceBrowserFullscreen() {
+    if (!isScreenSharingActive() || document.fullscreenElement) return;
+
+    beginNativePrompt();
+    if (document.documentElement.requestFullscreen) {
+        document.documentElement.requestFullscreen()
+            .then(() => {
+                endNativePrompt();
+                armTrailingBuffer(1000);
+            })
+            .catch(() => {
+                endNativePrompt();
+                showFullscreenRequiredModal();
+            });
+    } else {
+        endNativePrompt();
+        showFullscreenRequiredModal();
+    }
+}
+
+export function showFullscreenRequiredModal() {
+    if (!isScreenSharingActive() || document.fullscreenElement) return;
+    if (typeof window.Swal !== 'undefined') {
+        window.Swal.fire({
+            icon: 'warning',
+            title: 'Fullscreen Mode Required',
+            text: 'Your assessment must be conducted in Fullscreen mode while screen sharing. Please click below to enter Fullscreen.',
+            confirmButtonText: 'Enter Fullscreen Mode',
+            confirmButtonColor: '#6366f1',
+            allowOutsideClick: false,
+            allowEscapeKey: false
+        }).then(() => {
+            if (isScreenSharingActive()) {
+                enforceBrowserFullscreen();
+            }
+        });
+    }
+}
+
 // --- Screen Share Enforcement & Live Overlay Detector (Category 6) ---
 export function startScreenShare() {
     if (!navigator.mediaDevices || !navigator.mediaDevices.getDisplayMedia) {
@@ -361,26 +425,27 @@ export function startScreenShare() {
     .then(stream => {
         endNativePrompt();
         const track = stream.getVideoTracks()[0];
-        const settings = track.getSettings ? track.getSettings() : {};
 
-        // Enforce ENTIRE SCREEN share
-        if (settings.displaySurface && settings.displaySurface !== 'monitor') {
+        // Enforce ENTIRE SCREEN share across all browsers
+        if (!isEntireScreenShare(track)) {
+            track.stop();
+            screenShareStream = null;
+            logViolation('tab_switch', 'Candidate attempted non-entire screen share (tab or window)');
+
             if (typeof window.Swal !== 'undefined') {
                 window.Swal.fire({
-                    icon: 'warning',
+                    icon: 'error',
                     title: 'Entire Screen Share Required',
-                    text: 'You selected a single tab or window. You MUST select "Entire Screen".',
-                    confirmButtonText: 'Reshare Entire Screen',
-                    confirmButtonColor: '#6366f1',
+                    html: 'You selected a single tab or window.<br><br><b>You MUST select "Entire Screen" (or whole monitor)</b> to continue your interview.',
+                    confirmButtonText: 'Reshare Entire Screen Now',
+                    confirmButtonColor: '#ef4444',
                     allowOutsideClick: false,
                     allowEscapeKey: false
                 }).then(() => {
-                    track.stop();
                     setTimeout(startScreenShare, 300);
                 });
             } else {
                 alert('Entire Screen share is required. Please select Entire Screen.');
-                track.stop();
                 setTimeout(startScreenShare, 300);
             }
             return;
@@ -391,21 +456,9 @@ export function startScreenShare() {
         vidElem.srcObject = stream;
         vidElem.play().catch(() => {});
 
-        const btn = document.getElementById('share-screen-btn');
-        if (btn) {
-            btn.innerText = '🟢 Entire Screen Sharing Active';
-            btn.style.background = '#10b981';
-        }
+        updateScreenShareButton(true);
 
-        beginNativePrompt();
-        if (document.documentElement.requestFullscreen) {
-            document.documentElement.requestFullscreen()
-                .catch(() => {})
-                .finally(() => {
-                    endNativePrompt();
-                    armTrailingBuffer(1000);
-                });
-        }
+        enforceBrowserFullscreen();
 
         const interviewId = document.body.dataset.interviewId;
         if (typeof window.Peer !== 'undefined' && interviewId) {
@@ -417,10 +470,12 @@ export function startScreenShare() {
 
         track.onended = () => {
             screenShareStream = null;
-            if (btn) {
-                btn.innerText = '🖥️ Share Screen with Interviewer';
-                btn.style.background = 'linear-gradient(135deg, #6366f1 0%, #0078d4 100%)';
+            updateScreenShareButton(false);
+
+            if (document.fullscreenElement) {
+                try { document.exitFullscreen().catch(() => {}); } catch(e) {}
             }
+
             logViolation('tab_switch', 'Candidate stopped screen sharing');
         };
 
@@ -430,14 +485,50 @@ export function startScreenShare() {
         endNativePrompt();
         console.log('Screen sharing cancelled/denied:', err);
         screenShareStream = null;
-        const btn = document.getElementById('share-screen-btn');
-        if (btn) {
-            btn.innerText = '🖥️ Share Screen with Interviewer';
-            btn.style.background = 'linear-gradient(135deg, #6366f1 0%, #0078d4 100%)';
-        }
+        updateScreenShareButton(false);
     });
 }
 
+export function stopScreenShare() {
+    if (screenShareStream) {
+        try {
+            screenShareStream.getTracks().forEach(track => track.stop());
+        } catch(e) {}
+        screenShareStream = null;
+    }
+    updateScreenShareButton(false);
+
+    if (document.fullscreenElement) {
+        try { document.exitFullscreen().catch(() => {}); } catch(e) {}
+    }
+
+    logViolation('tab_switch', 'Candidate stopped screen sharing');
+}
+
+export function toggleScreenShare() {
+    if (screenShareStream && screenShareStream.active && screenShareStream.getVideoTracks().length > 0 && screenShareStream.getVideoTracks()[0].readyState === 'live') {
+        stopScreenShare();
+    } else {
+        startScreenShare();
+    }
+}
+
+export function updateScreenShareButton(active) {
+    const btn = document.getElementById('share-screen-btn');
+    if (!btn) return;
+    if (active) {
+        btn.innerHTML = '🛑 Stop Screen Sharing';
+        btn.style.background = '#ef4444';
+        btn.style.borderColor = '#dc2626';
+        btn.onclick = stopScreenShare;
+    } else {
+        btn.innerHTML = '🖥️ Share Screen with Interviewer';
+        btn.style.background = 'linear-gradient(135deg, #6366f1 0%, #0078d4 100%)';
+        btn.style.borderColor = '#6366f1';
+        btn.onclick = startScreenShare;
+    }
+}
+
 export function initLiveOverlayDetector() {
     if (overlayCheckInterval) clearInterval(overlayCheckInterval);
 
@@ -624,12 +715,13 @@ export function initCandidateProctoringListeners() {
         }
     }, 6000);
 
-    // 8. Fullscreen Exit Listener
+    // 8. Fullscreen Exit Listener (Only enforced when screen sharing is active)
     document.addEventListener('fullscreenchange', function() {
-        if (isFocusSuppressed()) return;
+        if (isFocusSuppressed() || !isScreenSharingActive()) return;
         if (!document.fullscreenElement) {
-            logViolation('tab_switch', 'Candidate exited full-screen proctoring mode (possible overlay AI window interaction)');
+            logViolation('tab_switch', 'Candidate exited full-screen proctoring mode while screen sharing');
             captureAndUploadTabScreenshot();
+            showFullscreenRequiredModal();
         }
     });
 }
@@ -1201,7 +1293,11 @@ if (typeof window !== 'undefined') {
     window.endNativePrompt = endNativePrompt;
     window.armTrailingBuffer = armTrailingBuffer;
     window.isFocusSuppressed = isFocusSuppressed;
+    window.isScreenSharingActive = isScreenSharingActive;
     window.startScreenShare = startScreenShare;
+    window.stopScreenShare = stopScreenShare;
+    window.toggleScreenShare = toggleScreenShare;
+    window.updateScreenShareButton = updateScreenShareButton;
     window.initLiveOverlayDetector = initLiveOverlayDetector;
     window.initQuestionRepeatDetection = initQuestionRepeatDetection;
     window.initCandidateProctoringListeners = initCandidateProctoringListeners;