Make background-color on homepage container div explicit
So I recently found out through an April Fools' Day accident that browser windows have a base colour, usually defined by the OS theming. Any element that doesn't explicate styling or inherit it from a parent element instead inherits it from this. The colour is usually #fff or other grayscale shade and so doesn't stand out, but when I on a whim installed the Windows-3.1-derived 'Hot Dog Stand' theme (Plasma version: https://github.com/ItzKaktus/hotdogstand-kdeplasma) I found that isn't always the case: