diff --git a/simple_analysis/templates/simple_analysis/simple_analysis.html b/simple_analysis/templates/simple_analysis/simple_analysis.html
index f475d40..4854f72 100644
--- a/simple_analysis/templates/simple_analysis/simple_analysis.html
+++ b/simple_analysis/templates/simple_analysis/simple_analysis.html
@@ -2759,32 +2759,19 @@ let _trafficCanvasCtx = null;
 
 function _ensureFlowLayer() {
     if (!SA.map) return null;
-    if (_trafficFlowLayer) return _trafficFlowLayer;
-    // Insert canvas AFTER map container, positioned to cover the map
+    if (_trafficFlowLayer && _trafficFlowLayer.parentNode) return _trafficFlowLayer;
     const mapEl = SA.map.getContainer();
     const c = document.createElement('canvas');
     c.id = 'saTrafficCanvasOverlay';
-    c.style.cssText = 'position:absolute; top:0; left:0; pointer-events:none; z-index:99999;';
-    // Insert after map container in DOM
-    mapEl.parentNode.insertBefore(c, mapEl.nextSibling);
-    // Size to match map
+    c.style.cssText = 'position:absolute;top:0;left:0;pointer-events:none;z-index:10000;';
+    mapEl.appendChild(c);
     const size = SA.map.getSize();
     c.width = size.x; c.height = size.y;
     c.style.width = size.x + 'px'; c.style.height = size.y + 'px';
-    // Position overlay over map
-    const mapRect = mapEl.getBoundingClientRect();
-    const parentRect = mapEl.parentNode.getBoundingClientRect();
-    c.style.left = (mapRect.left - parentRect.left) + 'px';
-    c.style.top = (mapRect.top - parentRect.top) + 'px';
-    // Update on map changes
-    SA.map.on('resize move zoomend', () => {
+    SA.map.on('resize', () => {
         const s = SA.map.getSize();
         c.width = s.x; c.height = s.y;
         c.style.width = s.x + 'px'; c.style.height = s.y + 'px';
-        const mr = mapEl.getBoundingClientRect();
-        const pr = mapEl.parentNode.getBoundingClientRect();
-        c.style.left = (mr.left - pr.left) + 'px';
-        c.style.top = (mr.top - pr.top) + 'px';
     });
     _trafficCanvasCtx = c.getContext('2d');
     _trafficFlowLayer = c;