[css-cascade-3] defines "origin" which conflicts with HTML

[jyasskin]

https://drafts.csswg.org/css-cascade-3/#origin defines origin as <dfn class="dfn-paneled" data-dfn-type="dfn" data-export="" id="origin">origin</dfn>, which collides with HTML's definition. You could add a for value to CSS's definition in order to disambiguate it.

[tabatkins]

Cascade 4 switches it over to "cascade origin", to avoid the conflict. I just updated Cascade 3 to use the same term. The TR versions will still have issues, tho. (I really need to get the obsoleting machinery working...)