border-box 兼容写法

@@ -119,7 +119,7 @@
         }
 
         .coupon-use {
-            box-sizing: border-box;
+            @include box-sizing(border-box);
             position: relative;
             float: right;
             padding-right: 30rem / $pxConvertRem;
@@ -137,7 +137,7 @@
                 color: #999;
             }
         }
-        
+
         .checkbox {
             display: inline-block;
             width: 80rem / $pxConvertRem;