when to modifier

packages/zanui-css/src/button.css

@@ -75,13 +75,13 @@
       font-size: 10px;
     }
 
-    @when disabled {
+    @m disabled {
       color: $button-disabled-color;
       background-color: $button-disabled-background-color;
       border: 1px solid $button-disabled-border-color;
     }
 
-    @when block {
+    @m block {
       display: block;
     }
   }

packages/zanui-css/src/button_group.css

@@ -2,6 +2,7 @@
   display: inline-block;
   box-sizing: border-box;
   padding-right: 10px;
+  vertical-align: middle;
   &:last-child {
     padding-right: 0;
   }