I use design frameworks to prototype and quickly release projects. Bootstrap and Material Design make it dead simple to create professional looking pages.
I use design systems to help manage my projects. Concepts like Atomic design, or finer nuances like Airbnb's methodology for class descriptors. It allows my team and I to organize our styles efficiently and effectively, and it gives a greater insight into the creation of styles (resulting in less refactoring over time).
At the end of the day it's hard not to bolt a Bootstrap Grid onto a project as a scaffold. It makes the CSS process more about colors and type than about the box model.