diff --git a/static/js/theme.js b/static/js/theme.js
index a35d786..39af3aa 100644
--- a/static/js/theme.js
+++ b/static/js/theme.js
@@ -17,8 +17,18 @@
         }
     }
 
-    // Restore saved state
+    // Restore saved state instantly — suppress transitions so there's no
+    // collapse animation flash on every page navigation.
+    sidebar.style.transition = 'none';
+    contentWrapper.style.transition = 'none';
     applyCollapsed(localStorage.getItem(COLLAPSED_KEY) === '1');
+    // Re-enable transitions after one frame so the toggle button still animates.
+    requestAnimationFrame(function () {
+        requestAnimationFrame(function () {
+            sidebar.style.transition = '';
+            contentWrapper.style.transition = '';
+        });
+    });
 
     if (toggleBtn) {
         toggleBtn.addEventListener('click', function () {