Hi Steve,
Here goes the default font-size set for the heading levels for example :
h1, .h1 {
font-size: 400%;
}
h2, .h2 {
font-size: 285.7%;
}
h3, .h3 {
font-size: 228.5%;
}
h4, .h4 {
font-size: 171.4%;
}
h5, .h5 {
font-size: 150%;
}
h6, .h6 {
font-size: 100%;
}
So the font-size will be calculated based on the parent/body font. If you body font is set to 16px, then the h1 font-would be 64px as it’s set to 400%. That’s for the default headings and if you use Responsive Headlines, you will be able to set your own compression ration.
Hope this makes sense. Let us know if you have any other question.