Make Navigation drop downs translucent?

Site URL: https://wolverine-ocelot-jsdw.squarespace.com/

Hi,

I'm trying to make the black background of the navigation drop downs, slightly transparent, about 25%.

The current CSS I have for the font color upon hover and background color is:

.header-nav-folder-content {
background: #000000 !important;
}

.header-nav .header-nav-item--folder .header-nav-folder-content .header-nav-folder-item:hover a {
  color: #3498DB !important;
  }

Thank you ahead of time!

Hi. It looks like you solved with this code?

.header-nav-folder-content {
    background: rgba(0,0,0,.15) !important;
    border-radius: 10px 10px 10px 10px;
}