* Style <button> and <input> elements explicitly instead of relying on browser defaults.
* Style jquery ui buttons the same way as regular buttons.
* Add color variables so we can restyle form inputs in dark mode.
* Standardize the upload widget background colors (light green for success,
light red for error).
* Move the progress bar to the bottom of the upload widget.
* Change the progress bar color to blue.
* Hide the "drag and drop a file here" message after a file has
already been uploaded.
Standardize background colors to light green or light red in several places:
* Modqueue positive/negative score backgrounds.
* Modqueue quality/sample warning backgrounds.
* User feedback positive/negative backgrounds.
* Ban expired/unexpired backgrounds.
* Flag resolved/unresolved backgrounds (removed; resolved flags no
longer have a grey background because of inconsistencies in what
resolved means).
Fineprint text was variously styled with `.info`, `.tn`, `.hint`, or
`.cost-footnote` css classes. Standardize on `.fineprint` instead. Use
`.hint` only for form hints and `.tn` only for <tn> tags in translation
notes.
Incidentally changes the font size of form hints to 0.8em (was 0.7em)
and the color of fineprint to #888 (was #AAA or #666).
Position <span class="hint"> elements to the right of normal <input>
elements and underneath <textarea> elements. Fixes form hints being
badly positioned on some pages.
