deactivation of the possibility to comment anonymously

[Carmen Hurst]

Hello, 
I tried to deactivate the possibility to comment anonymously on my blog?
I wrote the following code in the CSS File:

#select_blog_allow_anonymous_comments .ipsFieldRow .ipsClearfix{

display: none !important;

}

Unfortunately, it didn't work. 

Does anyone have an idea how I can solve the problem?
Thanks for your help!

[Carmen Hurst]

Hello,
does anyone have an idea, how I can solve this problem?