This ensures that the search form does not collide with the menu on smaller screens. Props sabernhardt, fedepia, Soean, lukecavanagh, mukesh27. Fixes #40398. Built from https://develop.svn.wordpress.org/trunk@51807 git-svn-id: http://core.svn.wordpress.org/trunk@51414 1a063a9b-81f0-0310-95a4-ce76da25c4cd