Ah, customizable for web developers, not end users.

(And yes, I'm still bitter about you all wrecking my scroll bars.)

You can override styling with user stylesheets. On desktop. Need the same for i{,Pad}OS.

I think that CSS is excessive, that I often disable it and that the excessive design means that sometimes the way to fix it is to add more stuff, which just makes it more messy. (In many cases, it would be helpful to put things that only the end user controls and that document author does not control. Yet, they don't really design them for that very well.)