Top margin on blog

I’m having a hard time with my top margins in a child theme of twenty twelve. Did some searching and tried css stuff in suggested places with no avail. But when I look at it with firebug it tells me the code isn’t coming from the style sheet at all.

html {
margin-top: 28px !important;

I seem to remember running into this once before on another theme and had to take this out of a php page but I searched though all the childs and the main theme pages and can’t find it.

Does anyone know what page has this thing and is there going to be any weirdness if I do remove it? I mean if they went to so much trouble to keep it what will happen if I nuke it?