diff --git a/src/ol/ol.css b/src/ol/ol.css
index 36845ba789..8c51bdad8c 100644
--- a/src/ol/ol.css
+++ b/src/ol/ol.css
@@ -60,6 +60,7 @@
   position: relative;
   height: 10px;
   z-Index: 9;
+  box-sizing: border-box;
   border: 1px solid black;
 }