Actually, for interactivity you don't have to use CSS but can also use SMIL animations to set SVG (or CSS) properties for things like clicking/hovering, timed transitions, and even animation sequences. Never understood the CSS march of progress narrative when CSS just piecemeally incorporares concepts (paint servers, filters, etc) SVG had for 20 years now, and what's so great about having those available in CSS" wild unchecked syntax, especially when you'd need (or prefer) JS anyway. SVG at least can be targetted as a reasonable output format by vector drawing tools.