diff --git a/lib/ui/css/grid.scss b/lib/ui/css/grid.scss
index e9ca19d..ac5f2c0 100644
--- a/lib/ui/css/grid.scss
+++ b/lib/ui/css/grid.scss
@@ -202,7 +202,7 @@
                             // }
                         }
 
-                        >em.bottom-border {
+                        >.bottom-border {
                             position: absolute;
                             bottom: 0;
                             left: 0;
diff --git a/lib/ui/grid/grid.js b/lib/ui/grid/grid.js
index 2079f82..b7a9118 100644
--- a/lib/ui/grid/grid.js
+++ b/lib/ui/grid/grid.js
@@ -2279,7 +2279,7 @@ export class Grid {
                 th.appendChild(spliter);
             }
             // bottom border
-            th.appendChild(createElement('em', 'bottom-border'));
+            th.appendChild(createElement('layer', 'bottom-border'));
             // tooltip
             // !nullOrEmpty(col.tooltip) && setTooltip(th, col.tooltip);
             header.appendChild(th);
@@ -2288,7 +2288,7 @@ export class Grid {
         const draggerCursor = createElement('layer', 'dragger-cursor');
         header.appendChild(
             createElement('th', null,
-                dragger, draggerCursor, createElement('div'), createElement('em', 'bottom-border')));
+                dragger, draggerCursor, createElement('div'), createElement('layer', 'bottom-border')));
 
         sizer.replaceChildren();
         this._var.refs.header = header;