I've spent the last week bringing UmBootstrap up to date with Bootstrap 5.3. I have background colours and shades working but custom opacity using utility classes is on my todo. Releases to come but in the meantime I have tested adding a new custom colour and shades without touching the Bootstrap Core files. So you can customise UmBootstrap without it breaking with Bootstrap updates… at least for now 🙂 https://cdn.discordapp.com/attachments/869656431308189749/1412697969110552607/UmBootstrap-2025-09-03_080659.mp4?ex=68b93d02&is=68b7eb82&hm=2640ac9f59353feda3c928263a3b6b8245d8c3e6160c72ca9d2346bad7935b65&