Re:future-proof? no such thing (Score 1)

As long as it adheres to the HTML 3.2 spec it is still standards-compliant. The W3C builds upon previous standards it doesn't break them. That's why they're "future-proof". You can still open a page done in HTML 3.2 and it will/should look the same as it was intended to. If you use a Doctype Declaration and follow the specs as outlined by the W3C, you shouldn't have a problem even when XXHXML 16.2.0.1.4 comes out. Standards are designed to be future-proof, follow them and your site will always work.