Add support for customizing the styles of public releases page

Right now all the public release pages look the same, and it would be a good feature if custom styles were allowed, maybe start with:

- Custom background color
- Custom text color
- Custom link color
- Custom font

This would allow users to have more ownership over their pages

No files, tests, or entry points are named. Start by locating the public release page implementation and reviewing how its styles are currently defined. Done should include a decided customization scope for background, text, link colors, and font, with the behavior verified on public release pages.

Written by the indexing model from the issue text.