I apply for CSS changes in the biography section:
The normal paragraph has the margin "1.5em 0". So the margin to the stuff above and to the stuff below is in both directions at least 1.5em. Thats good.
The 2nd level heading h2 has the margin of "0 0 0.875em 0". So the margin to the stuff below is at least 0.875em. But the margin to the stuff above is maybe 0.
If the stuff above a 2nd level heading is a paragraph, the margin-bottom of the paragraph is enough to keep distance. But if the stuff above is a table, there is not enough margin. the 2nd level heading is closer too the stuff above than to the stuff below.
So please change the margin for the 2nd level heading at least to "0.875em 0".
I didn't check the other heading levels. Maybe they have the same problem.