The migration to css-inline "fixed" the fact that styles from this
file previously were never applied to the internals of missed-message
emails.
Rewrite much of the CSS to more correctly scope to apply to the
appropriate elements, and document with comments the purpose of most
blocks.
Co-authored-by: Tim Abbott <tabbott@zulip.com>
This reverses the policy that was set, but incompletely enforced, by
commit 951514dd7d. The self-closing tag
syntax is clearer, more consistent, simpler to parse, compatible with
XML, preferred by Prettier, and (most importantly now) required by
FormatJS.
Signed-off-by: Anders Kaseorg <anders@zulip.com>