h3 are misaligned vertically on readme css (BB-6724)

The h3's (and below) on my overview readme are too high and don't look right. The reason being that they have a bottom margin of 5px and no top margin. This makes them appear to belong to the preceding paragraph instead of the one underneath. e.g.:

Blah blah blah.
.
HEADER3_TEXT
.
.
Blah blah blah.

Please remove the margin or add a larger one to the top of the h3.