Hi @blubbi91,

Please navigate to Dashboard > Forums > Settings > Styles admin page, put the following CSS code in "Custom CSS code" textarea. Save it, delete all caches and do Ctrl+F5 on front-end.

#wpforo #wpforo-wrap .mce-widget {
    background: #fff !important;
}
.mce-toolbar { 
    background: #fff !important; 
}

If it doesn't help, leave us your forum URL to allow us to check it and provide some sulution for you. 

Hello, nothing happened.

The site is not open, I create a test Account. it´s a German Website. The Forum is at "Community".

Thank you!

Hi @blubbi91,

Please remove the code I've provided and add this one:

.entry-content form button {
    background: #fff !important;
}

Please delete all caches, do CTRL+F5 (twice) on front-end.

A lot of thanks! 

You save my day.

nice Weekend 🙂