So, I read previous posts here and edited thickbox.css on my server. Here's my edit:
background-color:#E3EDF4; /*I changed this from black*/
filter:alpha(opacity=90);/*I changed this from 75*/
It just doesn't make any difference to how the gallery appears. And yes, I do have the thickbox effect activated on my gallery options page. Later I'd like to change the font of the thickbox gallery, but that seems hopeless if I can't even change the overlay color.
Any suggestions? Thanks! My gallery page is here.