How do you style elements in a loading state in CSS?

There is no <loading> element in HTML (which could be like a spinner)

There is no loading attribute, but we do have aria-busy.

There is a load DOM event, for like when an <img> is done loading.

If you fire an XHR request, I guess it's on you.

Other elements can need loading time, right? Canvas or something?

There is an obvious need to show people "loading" indicators.

There are 5 billion examples on CodePen. They are in use on TONS of websites.

HTML has a history of adding elements as needed. Should there be a semantic <loading> element for this purpose?

aria role