Built from ground up. Made to be as customizable as possible. Instead of Bootstrap, I create my own CSS framework. Why? Bootstrap 4 does not use CSS custom properties (variables) but only Sass variables. With CSS custom properties it would be possible to change variables on runtime and would be mush more straightforward to realize themes (like dark mode).
But I won't completely reinvent the wheel. Bootstrap gives you the option to only implement it's grid system, so I will keep using it.
What also could be great for Uisum 5.0, that it were more component-based.
