Incomplete list of mistakes in the design of CSS

For me, the mistake is having style attributes in html.

You should be able to write

<div color="red" font-weight="bold"/>

Instead of

<div style="color: red; font-weight: bold;"/>

These namespaces do not merge cleanly, for example `content`.

Oh for sure, its way way too late to do it, but I don't think much of any of the modern web stack would be kept if we designed in the 90s with what we know now.