Paul Irish on HTML element widths being inclusive of padding at all times. That is to say if I define my box as 200 pixels wide then it should stay at a total of 200 pixels, no matter what I use for its padding value.

The money shot is as follows:

* { /* apply a natural box layout model to all elements */
	-moz-box-sizing: border-box;
	-webkit-box-sizing: border-box;
	box-sizing: border-box;
}

Also, an interesting read on using * and its impact on performance.

You might get up in arms about the universal * selector. Apparently you’ve heard its slow. Firstly, it’s not. It is as fast as h1 as a selector. It can be slow when you specifically use it like .foo > *, so don’t do that. Aside from that, you are not allowed to care about the performance of * unless you concatenate all your javascript, have it at the bottom, minify your css and js, gzip all your assets, and losslessly compress all your images. If aren’t getting 90+ Page Speed scores, its way too early to be thinking about selector optimization.

As with most CSS, there’s no one-size-fits-all choice for this. At times it makes sense (it’s used on the WordPress.com Theme Showcase, selectively though) and at other times it doesn’t.

I like it, though.

Head over to Irish’s site to weigh in or drop a comment here with your thoughts.