Yes this is possible. You just need to append :hover to the end of any selector to make it’s styles only take effect when the user hovers their mouse over something. For example, if you had the following selector:
You would change it to:
For links, which commonly need a hover state, Microthemer suggest these hover selectors alongside others in the list. The screenshot you posted contained these hover selectors in the list.
For now, you will need to manually adjust the CSS selector code to append the :hover bit. You can do this by clicking the name of the selector you’re working on in the top toolbar. This will reveal the selector editing options where you can append :hover to whatever you see in the textarea.
Once we’ve rolled out the new interface improvements discussed here, we will make some significant improvements to the selector wizard so that manually updating selectors isn’t necessary in this circumstance.
I hope that helps, please let me know if you get stuck.