How are CSS and HTML a mess? Combined, they're an incredibly powerful layout engine that works almost the same across all environments and devices while also featuring easy accessibility.
Same for HTML. If the web would be reimagined today, there is a very low chance that we would create HTML as is.
second biggest problem is "no stricter mode". so even wrong or useless html/css code goes unflagged and is treated as it is normal.
CSS is way too powerful.
https://csszengarden.com/pages/alldesigns/
That statement wasn't true ages ago, and it's even less true now.