Reply To: Why does this positioning work the way it does

[shaneisme]

Your question (I think) is about how CSS works, not how positioning works.

The Cascade will follow importance, specificity and source order. So if you’re not being more specific with your selectors, or you’re not labeling things as important, if it’s further down the source it will overwrite stuff up above.

Of course in this case, you’re doing both, you’re being more specific by using a class and making it further down the source. If you use a code inspector, you’ll see that the CSS that was declared for just sup is being overwritten by sup.frac. In fact, the bottom: inherit on sub.frac is actually unnecessary.