[pierrec]

SVGs can contain CSS and Javascript, and even without that, you can make all kinds of animations completely in SVG markup, using SVG-SMIL. I'm just saying this as trivia, and emphatically do not recommend that you go down this collapsing rabbit-hole.

Ignore that the Wikipedia page currently calls it "a recommended means[1][2][3] of animating SVG-based hypermedia" (lol). It's a complex feature that browsers have been dragging along for years while nobody's using it. Though it seems that Chrome is finally taking the initiative of dropping support, or at least discouraging its use.