How to rotate a background image by less than 90 degrees

Hi all! I want to rotate a background image by about 20 degrees, but squarespace's built-in editor will only let me rotate the image by 90 degrees in either direction. Does anyone know some code I can put in that will allow me to rotate the image as much or as little as I want?

Thank you!

Ah sorry I found how to do this in the built-in editor in squarespace

If you need code, please share link to page where you added image, we can check easier