Update style.css to use GF API

[davelab6]

This is incomplete as the font family names change from "camelcase without spaces" to "title case with spaces" (eg RobotoFlex to Roboto Flex). Also note the the GF API version of Roboto Flex has no XOPQ axis.

Should there be a pair of " inside the url() with the parens?

I added the swap API url parameter to all the API URLs, too

[rodydavis]

I think there are a few places that need to be updated as well!

For example each of the steps import by name:
https://github.com/material-foundation/material-symbols-and-variable-fonts/blob/main/src/pages/steps/1.ts#L26