Visually connect tabs with tab content through a well
Don't mess with my CSS like this!
Use more down-to-earth z-index.

The effect is the same.
Remove deviations from stock bootstrap that caused problems

They came into oscar mostly in several-1000-lines commits with messages
like "dashboard improvements", so there's no way to find out why they were
added.
Reduce whitespace above black bar at the bottom and the form above
Undo border color changes that didn't catch all borders
Add CSS to vertically align plain text with the label in a horizontal form
Undo this bootstrap modification. It makes things harder to read.