diff --git a/packages/vant-css/src/button.css b/packages/vant-css/src/button.css
index 3ae0856c0..14e89483a 100644
--- a/packages/vant-css/src/button.css
+++ b/packages/vant-css/src/button.css
@@ -18,7 +18,11 @@
 
     &::after {
       content: " ";
-      position: absolute 0 0 0 0;
+      position: absolute;
+      top: 0;
+      left: 0;
+      right: 0;
+      bottom: 0;
       background-color: #000;
       opacity: 0;
     }