Question

Is the order, or sequence, of rules in CSS significant?

This post says that it matters: Order of CSS rules matters!!!!!!!!!!

I haven’t noticed anything about this in the CSS spec.

Should Calculating a selector’s specificity say that if-and-only-if two rules have the same specificity, then it’s the later of the two rules (i.e. whichever rule is defined after the previous rule) that’s the effective rule?

Answer 1

Order does matter. If the specificity is equal, the rule declared later wins out. See Cascading Order in the spec:

…Finally, sort by order specified: if two declarations have the same weight, origin and specificity, the latter specified wins. Declarations in imported style sheets are considered to be before any declarations in the style sheet itself.