If you want to write web apps, save the HTML for last. When you are writing apps for yourself you write just what you need. That is what I am saying. Functional HTML first. It's not hard to write plain looking but very good UX. I think we are agreeing. I meant write stuff that works but is not fancy and avoid the big JS frameworks.

Yes, I agree. Sometimes (maybe often?) plain HTML and CSS with a little bit of Javascript (and server-side logic) works perfectly fine for many "web apps". It can even be faster (and simpler) than downloading all the app logic and a fat Javascript library to the client.

That's why It's a good thing to develop mobile-first, you tend to keep things more minimal.