If you want to test a minor style change on your latest promotion, try the Clone Theme tool! Use it to clone your current theme, so you can try new styles without losing your old settings.
To clone your theme, select any existing theme in your account and click “Create Theme”
Choose “Clone Current” at the pop-up and don’t forget a nice title :)
The cloned theme appears at the bottom of your list. Now it’s time to experiment!