diff --git a/webui/static/init.js b/webui/static/init.js
index e6ea4816..4da3795f 100644
--- a/webui/static/init.js
+++ b/webui/static/init.js
@@ -404,6 +404,10 @@ async function initProfileSystem() {
 function showLoginScreen() {
     const overlay = document.getElementById('login-overlay');
     if (!overlay) return;
+    // Hide the entire app while locked, so removing the overlay (Safari "Hide
+    // Distracting Items", devtools) reveals nothing — not even the empty chrome.
+    // initApp() reveals it again on a successful sign-in (#852).
+    document.body.classList.add('app-locked');
     overlay.style.display = 'flex';
     const u = document.getElementById('login-username');
     if (u) setTimeout(() => u.focus(), 50);
@@ -507,6 +511,8 @@ async function submitRecoveryReset() {
 function showLaunchPinScreen() {
     const overlay = document.getElementById('launch-pin-overlay');
     if (!overlay) return;
+    // Hide the whole app while locked — bypassing the overlay reveals nothing (#852).
+    document.body.classList.add('app-locked');
     overlay.style.display = 'flex';
 
     const input = document.getElementById('launch-pin-input');
@@ -2322,6 +2328,10 @@ async function _continueAppInit() {
 }
 
 function initApp() {
+    // Unlocked / authenticated — reveal the app (the lock screens hide it via
+    // body.app-locked so a bypassed overlay shows nothing). Do this FIRST so
+    // component init below measures real layout, not a display:none container.
+    document.body.classList.remove('app-locked');
     // Initialize components
     initializeNavigation();
     initializeMobileNavigation();
diff --git a/webui/static/style.css b/webui/static/style.css
index 69f45953..954ff067 100644
--- a/webui/static/style.css
+++ b/webui/static/style.css
@@ -68177,3 +68177,13 @@ body.em-scroll-lock { overflow: hidden; }
     .arec-row { grid-template-columns: 1fr; gap: 2px; }
     .arec-rowcopy { opacity: 1; justify-self: end; margin-top: -22px; }
 }
+
+
+/* #852: while the launch-PIN / login lock screen is up, hide EVERYTHING in the
+   body except the lock overlays themselves — so removing the overlay (Safari
+   "Hide Distracting Items", devtools) reveals a blank page, not the empty chrome
+   or any of the on-demand modals/sidebars. The hide-element trick can only ADD
+   hiding, never undo this rule. initApp() drops body.app-locked once authenticated. */
+body.app-locked > *:not(#launch-pin-overlay):not(#login-overlay):not(script):not(style):not(noscript) {
+    display: none !important;
+}