box-sizing
Widely available since 2018-01-29
The box-sizing CSS property sets whether an element's width and height are calculated based on the content-box, which does not count the size of borders or padding, or border-box, which does count them.
Learning resources on MDN
Browser support (view on caniuse.com)
- Chrome 10 Released on 2011-03-08
- Chrome Android 18 Released on 2012-06-27
- Edge 12 Released on 2015-07-29
- Firefox 29 Released on 2014-04-29
- Firefox for Android 29 Released on 2014-04-29
- Safari 5.1 Released on 2011-07-20
- Safari on iOS 6 Released on 2012-09-10