Maximise your browser's window. Go to Site administration ► Appearance ► Themes ► Theme settings. Make sure Theme designer mode is unchecked. Create some Custom menu items. You may use the the given example. Save the changes. Use the Clean theme. (Site administration ► Appearance ► Themes ► Theme selector) Confirm that the nav bar with its menus are being properly displayed. Open your browser's inspector. Inspect the Styles associated with the div with the class " nav-collapse collapse " Confirm that you can see the @media rule with a min-width set to 980px . Confirm that enclosed in the @media rule, the following styles are listed: .nav-collapse.collapse { height: auto !important; overflow: visible !important; } Confirm that the default .nav-collapse.collapse is being overridden by the .nav-collapse.collapse in the @media rule. Optionally, repeat the above tests using the More theme or other Bootstrap-based theme. Other variables Install grunt. ( Click for more info ) Copy test.less to theme/bootstrapbase/less . Replace your Moodle installation's Gruntfile.js with the attached Gruntfile.js . Open a terminal and go to your Moodle installation's root folder. Enter grunt css Check the generated test.css file in theme/bootstrapbase/style . Confirm that test.css file is valid. (You can check for CSS validity here ). Search in the file for the following: +.*\d -.*\d %.*\d \\.*\d and friends - you shouldn't find them.