relative path on images/css?

We are going through a rebrand, which means several domain name changes. This includes our Marketo domain.

To prepare for the switch-over, I've been able to replace things like the domain name in hrefs, and our company name wherever that will appear. What remains is images and links to css. I know I can do tokens for these, and it'll work in the end result - but it makes viewing and working on stuff in the backend quite a bit harder.

Is there any way to use a relative path, or some other method? like ../css/styles.css?  I don't know what relative path would do the trick, or if it's possible.