This fixes a visual regression in newer Electron builds (without
regressing Firefox) for which I still don't entirely know the root
cause, where extra "borders" were being applied to messages in both
streams and PMs. Applying a negative "spread radius" to the box-shadow
properties of these elements, and moving that pixel to the "horizontal
shadow" aspect of the property (which is used to create the left-side
"ruler" effect), restores the expected look and feel.
Tested in qutebrowser (Chromium 87-based), Electron v18+v19, and Firefox
107.
Refs (and should unblock) zulip/zulip-desktop#1251
This is part of redesigning messages (#22059). This commit adds
classnames to messages with mentions, differentiating direct mentions
from wildcard mentions from usergroup mentions, and this set us up
for a future commit where we'll have those different kinds of messages
be displayed in different colors.
Josh Klar
evykassirer
Anders Kaseorg