I'm not sure, because I haven't tried it, but: assume the markup and scripts are locked down, and you're only offered CSS as a means to theme a site's look & feel – how then would the SVG markup get on the page? Such was the case for our customers' sites at the company where I made this: everyone got the same markup in their widget, and changing that (for example, to add some SVG elements) was a more involved release process than just updating their CSS overrides.

Not 100% sure, but if you inline an SVG in HTML, you should be able to style it using CSS the usual way.

True, that is my understanding as well – still, though, requires that you have that SVG in your HTML in the first place. The CSS approach (in my link anyway, not necessarily OP's) can be incorporated without any updates to your existing markup – even without adding a single DIV.