No, the element's height does not need to be greater than or equal to the height. It often isn't by default and this is normal behavior in browsers. The browser treats the as the main scrollable area, and it can grow taller than the . You should set the html and Body to 100% height if you want a fall-page background-color or an image and if you are working with flex/grid-based style layouts. This will prevent you from scorlling issues or having layout glitches.