Can a Website be 100% Bootstrap?

Hi, I’m new to bootstrap, so Im reading everything I can to build a website for a project. But, as everything, I find that there’s no way to write a 100% pure bootstrap site, maybe people patch in solutions their own way, maybe there’s no ‘iron’ how-to guidelines, or maybe the system isn’t thought to be used to write a 100% pure bootstrap code. I’m guessing here.

So, Im approaching my bootstrap theme development this way:
1.- when I OK the design, the next step is build a bootstrap hardcoded mockup as much alike the design, so I can test the behaviors, etc;
2.- then add or modify the css to fit the design;
3.-and the last step is to integrate it to the WP theme with all the code and smooth out all the problems that may arise.

I’m a self tought designer and developer, so my formation is not strictly clean, but for I’ve looked around about using bootstrap, I think I might be on a “good” path… Am I right?