Code to reduce size of Header in custom CSS file

I have been trying to reduce the size of my header, h1. One css website suggested the following code, which I added to my Custom Stylesheet CSS file in Backlight, but it does not work.

height: 70%;
width: 70%;

Any suggested code that would work?

try this instead:

h1 {
font-size: 1.75em;

And adjust as needed. The default size is 2em (1em = 16px)

Thanks Rod, this seems to work. I set it at 1.5em, and the headings look much nicer. When I tried it at 1.75em, I didn’t notice any change.

Might have been a syntax error. When I change it in the inspector, there is a definite difference.