Is it wrong to change a block element to inline with CSS if it contains another block element?

Question

I know it\'s wrong to put a block element inside an inline element, but what about the following?

Imagine this valid markup:

This         


        
      

Answer 1

The HTML is validated independently of the CSS, so the page would still be valid. I'm fairly sure that the CSS spec says nothing about it either, but don't quote me on that one. However, I'd be very careful using a technique like this, as while it might render as intended in some browsers, you'd need to test 'em all—I don't see many guarantees being made.