A floating action button in HTML & CSS
HTML & CSS interview exercise on Positioning & stacking, difficulty 2 of 3. Solve it in the editor beside a worked example, or cold in Interview mode with the example hidden; the tests run the moment you do.
Float the button in the bottom-right corner of the viewport, 24px from each edge, as a 56px round button that stays there while the page scrolls and sits above the content. The main content must not be pushed around by it.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Interview mode hides the example: solve it from memory, without the hint or the solution, and it counts as solved cold. Progress is saved in your browser, and in your account if you sign in.