Fix dropdown menu formatting; less-ify containment in `kujua-visual` CSS.

The dropdown menus kind of look like the buttons are sticking their tongues out
now. I think I like it; I just need to figure out a different style (probably
something popup-like) for the shrunk dropdown buttons on mobile/small-width.
Dropdown button/menu style tweaks.
I can't look at that puke yellow color anymore. Rotating colors for sanity.
Color tweaks to actions panel, in preparation for adding icons/labels.