If I use the customizer to add some styles to headings. h2 for example.
Then it’s totally impossible to edit that h2 with a higher specificity. line-height is what is the problem.
So I had to drag all the settings to 0 to be able to edit my other styles.
So I do some styles for h2 in the customizer like font-size 36px, line-height 1.2em.
Then I want to have another style for a specific div. So I set up a CSS rule like div h2.special-div and edit the styles to for example font-size 24px, line-height 0.9em.
It does not have any effect at all.