Changing Blog Titel (Post Overview Title)

Hi,
I want to integrate on my page http://www.felix.ch an Blog with different post. I’m planning to use the modern Blog Style. On the Page I integrate the blog with Raster Layout with title and read more. Unfortunate the title is in a style that I don’t like. Way to big and capitalized. I would like to change this.

I changed it in Quick CSS and add follow:

.entry-content-wrapper .post-title {
font-size: 16px !important;
}

Unfortunate this doesn’t work. I spend the layout.css file and changed the 2.5em to 1.5em under Modern Blog -> but this doesn’t work ether.

Now I need some help please.
Best Katharina