Fun to see how apparent boundaries can be pushed or broken with clever use of lesser known features.
That said, most of this is probably better done with CSS today.
My only professional exposure to SVG was when a pen tester found my predecessor's code had unintentionally allowed them, and that one can do injection attacks from the SVG itself. Of course this was around the time a client discovered SVG worked for them, so I had to make support official and defeat injection attacks. Good times.