Editor: UX/design improvements

[goldpbear]

This is a catch-all issue for changes we'd like to make to the UX or visual design of the rich text editor interface and/or other elements of the editor.

• The styling and spacing of certain elements in the rich text editor is not faithful to what is rendered in place detail views after editor changes are saved. There are probably conflicting CSS rules in play; we should untangle these conflicts and decide on a single visual style to enforce.
• "Big button"-style radio and checkbox controls are too faded to be easily legible when unselected.