How to easily edit my site remotely?

So, mostly asking about themes here. When I made a custom local theme, I simply went in and changed CSS/HTML and clicked save. Well, now I host my custom theme on GitHub, but it is beyond annoying for any tiny little change I want to make, I have to make the change, push it to GitHub, then update my theme in Admin panel just to see the tiniest changes I’m making. Is there any easier way?