Search results are completely invisible on narrow screens

My Android phone has 1080 x 2400 pixels (170 x 78.1 mm). Activating the search bar has no visible effect in either Chrome or Firefox.

You can also reproduce this on a Desktop browser: Activate the search results first, then shrink the window horizontally. In the attached screenshots, search-narrow-phone.png is only 2 pixels narrower than search-wide-phone.png