This is an esthetic issue, but to my eye there is too much space above the <h2> to <h6> headings. So much that when I was working on a new article (https://developer.mozilla.org/en-US/docs/Project:MDN/Contributing/Live_samples), I went back into it to see if I had accidentally inserted some blank lines in the source text. But I hadn't; extra space was caused by the styling.
In general, it feels to me like there is a lot of vertical space in the textual layout -- between paragraphs, between list items, etc. But the headings are the part that made me do a double-take.
Sean proposed some styles, I implemented, and we agreed it wasn't working, so this will be fixed momentarily.
I think this is fix: Janet can you confirm?
Yes, looks much better in that regard.