No, there is a specification for HTML5, and it does exactly what I said it does. Granted, most &quot;HTML5&quot; is a mix of HTML 4 and HTML5 (sometimes even a little XHTML) but these are not strict validated sites.<p>Here, try running a few websites through <a href="https:&#x2F;&#x2F;validator.w3.org&#x2F;" rel="nofollow">https:&#x2F;&#x2F;validator.w3.org&#x2F;</a> and see what pops up. You&#x27;d be surprised.<p>For example, <a href="https:&#x2F;&#x2F;news.ycombinator.com" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com</a> is extremely bad HTML5, and if you look at the report on it, <a href="https:&#x2F;&#x2F;html5.validator.nu&#x2F;?doc=https%3A%2F%2Fnews.ycombinator.com&amp;showimagereport=yes&amp;showsource=yes" rel="nofollow">https:&#x2F;&#x2F;html5.validator.nu&#x2F;?doc=https%3A%2F%2Fnews.ycombinat...</a> you can see a bunch of &quot;Use CSS Instead&quot; suggestions. This is the separation of style from semantics that HTML5 was made to reinforce.