how to use the Custom CSS tab

Hello how are you?

I’m trying to align the name and price of the product at the top, as you can see in the print, I pasted one of the codes that worked in the dev tool but it’s not working when I send a test.

I use your size chart plugin and I used the same mechanic to customize the tables but in this plugin I tried to paste several codes from the dev tool and was unsuccessful.

My doubt is how to align these items and how to get the css codes in the right way because the ways I tried none of them worked for me.