[whatwg] Bad CSS on the multipage version

[Křištof Želechovski]

Regarding your page at the URL
<http://www.whatwg.org/specs/web-apps/current-work/multipage/text-level.html
#the-embed>:
The following declaration is bad and wrong:
Is: "margin-top: -2.5em"
Should be: margin-top: -2.5ex"
Wrong: A horizontal unit is applied to a vertical measure
Bad: 
Element headings (level 4) are invisible 
(obscured underneath the following content).
Please fix ASAP.
Chris