Having used mhonarc for few years back.. lore.kernel.org had me curious.
Minimal, arcane stuff... ;)
1. Mbsync email to a folder (optional)
2. Create a config and got repo with public-inbox-init
3. Edit the config to add 'watch' for the maildir or you can ask it to watch imap folder.
4. Run public-inbox-httpd for the site and public-inbox-imap-watch to populate
Oh.. did I need say? The concept of user color customization is user will create his/her own css and set it up on browser.
Linux geeks doing what Linux geeks do...