This didn't apply cleanly before; fixes display of rawhtml in prefs page
Some tweaks to CSS changes
Revert "Revert "Improved centering of redbox""

This reverts commit 3c78254589808532dcd1bc88ac70fb90e7e3fe1a.

Without this, certain IMP redbox items are unreadable
application-specific max-width
Fix redbox positioning
Don't grab column information unless/until needed