diff --git a/umap/static/umap/map.css b/umap/static/umap/map.css
index baf8fa3b..a3df4b8b 100644
--- a/umap/static/umap/map.css
+++ b/umap/static/umap/map.css
@@ -1436,7 +1436,7 @@ span.popup-icon {
     margin-left: 10px;
 }
 .leaflet-top {
-    z-index: calc(var(--zindex-panels) + 1);
+    z-index: calc(var(--zindex-panels) - 1);
 }
 .leaflet-popup-content {
     min-width: 200px;