This is what user stylesheets were intended to solve. Too bad the majority browsers have gone down the path of attempting to remove all customisation.
Look at the source code of Twitter or Facebook. It's intentionally obfuscated and mangled, probably in part to fuck with ad blockers.
I have a few user stylesheets (even a little custom Firefox extension to block one user's comments on a site I frequent), but the sites I'd really like to use them on largely don't make it possible to do so.
Look at a Facebook ad in your browser's web inspector, for example. The "Sponsored" tag is made up of 31 different randomly named span tags. https://imgur.com/a/AHZL8ko