Aggressive display: hidden; in WP admin

There is some code in the bootstrap.css file which causes problems:

.hidden {
  display: none !important;
}

See here:
https://lakeshorewoods.rocks/screenshots/2017-11-02_17-14-01.png

This code is being applied to the WP admin, preventing the normal behavior of the “Screen Options” and “Help” slide downs at the top-right of the dashboard.
Can the !important be removed so the WP UI can operate normally?

The page I need help with: [log in to see the link]