“This is a line with quotation marks and the line’s got an apostrophe, too.”
Em-dashes work—that we know. And en-dashes work also, from 2026–. “‘Nested’ quotes?” They seem fine, though the spacing is sub-optimal.
We already know that equations work well:
π=4−3!4−5!12−7!180−9!6300−11!396900−⋯=n=1∑∞(2n−3)(2n−1)!−4((2n−3)!!)2.
Inline math also: (x1+x2)+(x1x2)=c.