Comment by red_admiral

From past experience (may be different now): Typst supports SVGs that are actually vanilla SVGs. The SVG standard lets you embed a HTML page and CSS as a <foreignObject>, which only renders properly in a browser or something that bundles one (surprise!). This is not the fault of Typst and I think Typst is correct not to go down that route.

Just a heads up if you wonder why draw.io (diagrams.net) SVGs display as black boxes.