No, it's built using tabler.io. Tabler is built on top of Bootstrap 5. It's actually what we already use for our admin panel, we have some familiarity of it as a team.
The decision to go with Laravel was done back when we started the project. Since then, stuff changed and the current codebase is in a point where a full rewrite doesn't seem vital at all. The reasons are explained in more detail here: Future FOSSBilling roadmap - Dropping the Laravel branch
No matter what you've chosen to go with, thanks for the support and being an active part of the community ♥️.
I don't know why the word "Blesta" is censored though. I don't think we have any automod rules or anything, feel free to use the word 😄.