Ready Review Theme | Change Font Menubar

I hope I am right here, just signed up at the forum and somewhat of a wordpress newbie as well.

Although I made quite some progress with my WP skills in the last days already I can not seem to figure this simple thing out:

I want simply to change the font size,font style and attributes alike of my menu bar.
I searched many google threads already but all these css edits do not seem to help.

This is my page

https://www.dashabichprobiert.de

I just want to edit the menu bar ??
I am using the ready review theme.

the only half working code so far i found is

.main_menu{
font-size:25px;
font-family:”Times New Roman” !important;
}
.main_menu li a{
color:#ff0099 !important;
font-weight:bold;
}

but the weird thing is,this will just change the font to times new roman but will not increase the font whatsoever

please help ??

kindest regards
Das Hab Ich Probiert