How to disable UPPERCASE transformation for headings

Hello,

does anybody know how I can disable that every heading is transformed to UPPERCASE in this theme?
I tried adding “text-transform: none;” in style.css for h1, h2, … but it did not help.

I also added this to style.css but it did not help:

h1, h2, h3, h4, h5 {
text-transform: none !important;
}