Hi There @nikolaus.kemetner
Thanks for writing in!
1.You can add the following CSS rule into your X -> Theme Options -> CSS area.
2.Could you please try disabling your 3rd party plugins to see if you're experiencing a plugin conflict. If not, If you have an active child theme, try switching to your parent theme and see if you're experiencing any issues with your child theme.
3.If you follow our translation guide here (https://theme.co/apex/forum/t/setup-translation/61), you should be able to locate those strings.