I took this approach for https://legiblenews.com/ and https://www.thingybase.com/. The art on Thingybase is all poorly drawn stick figures that I sketched out on my iPad.

Not only do I recommend doing this when building apps or websites initially, but I recommend it for the final product. It ends up being much faster, easier to maintain, easier for people to read, and more accessible.

I have another app in the works that’s using https://picocss.com/ with basically no CSS. It’s great not having to think too much about design elements and focus on only the most important bits of the application.