Thanks! My only problem with it is that, on mobile, it stays fixed to the device height, even when the content is longer. When I make it fill the entire body, it streches across all the content, but stops at the bottom edge of the page content, leaving an ugly white area on desktop.
Does anyone have an idea, how I can make it stretch across the whole body, while also stretching to the viewport height if the content doesn't reach the bottom edge?