Replaced elements absolutely positionned

[nico3333fr]

Hi,

just below "Position and width", it could be good to mention "replaced elements absolutely positionned", which is quite… wtf.

Here is the text you could add:

Don't use width… except if you are in the case of a replaced element that is absolutely positionned. I this case, there are some weird and difficult to understand rules that apply. Specially in this case, the browser will ignore the right value. It is not a bug, it is a feature of the spec.

Here is a pen that explains it : http://codepen.io/nico3333fr/pen/wBQJWe

Do you want a PR for this ?

See you, Nicolas