Add "Add" and "Remove" buttons beneath thumbnails on the /ai_tags page.
These let you add the tag to the post if it's correct, or remove it if
it's wrong.
Fix buttons appearing to be clickable when in the disabled state.
Submit buttons are normally disabled after a form is submitted. Before
these buttons would still look clickable. Now disabled buttons are greyed
out instead of looking the same as normal buttons.
Add a new color palette and rework all site colors (both light mode and dark mode) to
use the new palette.
This ensures that colors are used consistently, from a carefully designed color palette,
instead of being chosen at random.
Before, colors in light mode were chosen on an ad-hoc basis, which resulted in a lot of
random colors and inconsistent design.
The new palette has 7 hues: red, orange, yellow, green, blue, azure (a lighter blue), and
purple. There's also a greyscale. Each hue has 10 shades of brightness, which (including
grey) gives us 80 total colors.
Colors are named like this:
var(--red-0); /* very light red */
var(--red-2); /* light red */
var(--red-5); /* medium red */
var(--red-7); /* dark red */
var(--red-9); /* very dark red */
var(--green-7); /* dark green */
var(--blue-5); /* medium blue */
var(--purple-3); /* light purple */
/* etc */
The color palette is designed to meet the following criteria:
* To have close equivalents to the main colors used in the old color scheme,
especially tag colors, so that changes to major colors are minimized.
* To produce a set of colors that can be used as as main text colors, as background
colors, and as accent colors, both in light mode and dark mode.
* To ensure that colors at the same brightness level have the same perceived brightness.
Green-4, blue-4, red-4, purple-4, etc should all have the same brightness and contrast
ratios. This way colors look balanced. This is actually a difficult problem, because human
color perception is non-linear, so you can't just scale brightness values linearly.
There's a color palette test page at https://danbooru.donmai/static/colors
Notable changes to colors in light mode:
* Username colors are the same as tag colors.
* Copyright tags are a deeper purple.
* Builders are a deeper purple (fixes#4626).
* Moderators are green.
* Gold users are orange.
* Parent borders are a darker green.
* Child borders are a darker orange.
* Unsaved notes have a thicker red border.
* Selected notes have a thicker blue (not green) border.
