To change opacity of Dropdown Background, you can use CSS code like this to Custom CSS box.
div.header-nav-folder-content { background-color: rgba(51,8,247,0.5) !important; }
Note: 0.5 is opacity.
Result
To change opacity of Dropdown Background, you can use CSS code like this to Custom CSS box.
div.header-nav-folder-content { background-color: rgba(51,8,247,0.5) !important; }
Note: 0.5 is opacity.
Result