Style site home page

[mojavelinux]

Add CSS to style the site home page (i.e., site start page). To keep the complexity to a minimum, we should start by using a page role (home) to load an additional stylesheet named home.css. If we decide we need to do more with the home page in the future, we can introduce a template.

To begin, the home page should feature two UI components:

• a hero-like panel made from an open block with the role "panel"
• a row of cards arranged as a grid made from a description list with the role "grid"