Bootstrap
What is Bootstrap and how does Ultimate Database utilise it?
Bootstrap is a framework for managing consistent and responsive design across a website. It is used extensively within UDB.
While it would be possible to create a site on UDB without Bootstrap, it would be very difficult and you wouldn't be able to include the front end site maintenance.
99% of bootstrap has been left using the default CSS but a few modifications have been made in the core UIUDB CSS to allow the system to work a bit better.