diff --git a/elements.less b/elements.less
index 607f3b6..df4d2ff 100644
--- a/elements.less
+++ b/elements.less
@@ -233,3 +233,34 @@
     column-rule-width: @columnRuleWidth;
   }
 }
+
+#box {
+    .border-box() {
+        -moz-box-sizing: border-box;
+        -ms-box-sizing: border-box;
+        -webkit-box-sizing: border-box;
+        -o-box-sizing: border-box;
+        box-sizing: border-box;
+    }
+    .content-box() {
+        -moz-box-sizing: content-box;
+        -ms-box-sizing: content-box;
+        -webkit-box-sizing: content-box;
+        -o-box-sizing: content-box; 
+        box-sizing: content-box;
+    } 
+    .padding-box() {
+        -moz-box-sizing: padding-box;
+        -ms-box-sizing: padding-box;
+        -webkit-box-sizing: padding-box;
+        -o-box-sizing: padding-box;
+        box-sizing: padding-box;
+    } 
+    .margin-box() {
+        -moz-box-sizing: margin-box;
+        -ms-box-sizing: margin-box;
+        -webkit-box-sizing: margin-box;
+        -o-box-sizing: margin-box;
+        box-sizing: margin-box;
+    }
+}