h5bp/html5-boilerplate — pull request #1403 by ArloL (2013-07-10 15:16:10+00:00)
Title: Set color for disabled form elements

Setting the color on form elements (e.g. button) also overwrites the disabled styles of the user agent: http://jsfiddle.net/rmHKu/1/

Therefore it is necessary to explicitly set the disabled style: http://jsfiddle.net/LfAUR/1/