additional CSS not working

Hey! I`m using the Fotografie theme (love it) and would like to change a few things like removing featured image from posts and removing the title from posts page. I already did that with additional CSS I found here. But for a few weeks now it doesn't work anymore. Tried pretty much all the CSS I could find, but it doesn't have any effect. https://raysgeardesigns.com/blog/ best regards derray