> but they don't have a huge, heavy set of components and requirements like Bootstrap.

But that's all optional, Bootstrap is modular [1] [2] [3].

[1] https://getbootstrap.com/docs/3.3/customize/

[2] https://github.com/twbs/bootstrap-sass/blob/master/assets/st...

[3] https://github.com/twbs/bootstrap/blob/v3-dev/less/bootstrap...