Change Dropdown Menu Background from Transparent to Black

Site URL: https://leadersbloom.com/

I have read all the other posts and tried the CSS provided and not able to change my dropdown menu background from transparent to black like the header.  I am working in Developer Mode if that makes a difference. Also in an older version.  Thank you!

Custom css 

/* Change the navigation drop-downs to solid black background colour  */
 #topNav nav .folder-collection ul li a {
   background-color:##000000;
 }

Try this CSS (Add to Home > Design > Custom CSS)

.folder-child-wrapper {
    background: black !important;
}