tweak/styling_improvements

Inline NPCs use images not backgrounds
Inline NPCs have a background colour





Columns, abilities, npc lists now work in posts
NPC lists use images not backgrounds
Columns use flex (like they were supposed to!)

Fix for this triangle (dark, conversation mode, backfill).

Do we actually need the borders on the backfilled posts?
I found it strange that they did not fade away and --since it keeps the page scrolled to where you were-- I don't see their value, we already know which ones are 'new'.

They are easy enough to ignore, but seem out of place and unnecessary.

Good point. I would be for removing those as well

...and they only appear in dark mode. I think it's a hangover from the old ported extension code. Removed.