Photoset Opacity

Copy and paste this code in Customize>Advanced Settings.
There should be a box that is labeled "Add Custom CSS."

code begins here:

iframe.photoset {
 opacity: .80; -webkit-transition: all 0.6s ease-out;
-moz-transition: all 0.6s ease-out;
transition: all 0.6s ease-out;
}
iframe.photoset:hover {
 opacity: 100; -webkit-transition: all 0.6s ease-out;
-moz-transition: all 0.6s ease-out;
transition: all 0.6s ease-out;
}
iframe.photoset {
 opacity: .80; -webkit-transition: all 0.6s ease-out;
-moz-transition: all 0.6s ease-out;
transition: all 0.6s ease-out;
}
iframe.photoset:hover {
 opacity: 100; -webkit-transition: all 0.6s ease-out;
-moz-transition: all 0.6s ease-out;
transition: all 0.6s ease-out;
}