Targeting text with Quick CSS.

I would like to have different sections of text on my pages designated as h1, h2, h3 etc. so that I can target them in Custom CSS to change font sizes on a mobile device. The problem that I am having is that once I designate a section of text as h1, for example, the letters are all caps. How can I make it so that I am able to use uppercase and lowercase leters for h1,h2,h3 text?

Thank You.