CSS - Box-sizing
The box-sizing CSS property is used to alter the default CSS box model used to calculate widths and heights of elements. It is possible to use this property to emulate the behavior of browsers that do not correctly support the CSS box model specification. -- MDN Box sizing
Accepted values: content-box (default), padding-box, border-box, inherit
Implementation with vendor prefixes borrowed from CSS3 Please!
* {
-webkit-box-sizing: {{boxModel}}; /* Android ? 2.3, iOS ? 4 */
-moz-box-sizing: {{boxModel}}; /* Firefox ? 28 */
box-sizing: {{boxModel}}; /* Chrome, Firefox 29+, IE 8+, Opera, Safari 5.1 */
}