How do I change colorbox background opacity?

Hi – I really want to make this plugin work for me. I’m tending to prefer the simple colorbox option which is the white one that’s in the middle of the top row of options.

However… the slight transparency of the white background allows the print of the underlying page to come through and it actually clashes or interferes with the text of the colorbox image caption. How can I change the background to be 100 percent opaque? And for that matter, is it possible to change the caption text color and font, and the background color? I have no knowledge of php and java, but if someone points me in the right direction, I can copy and paste in the plugin editor.

Also, incidentally, there’s a weird little bug in the settings for this plugin. When you try to change the %title% to %caption%, you can’t really do it because for some invisible reason that field only accepts a certain number of characters so you always end up with ption% instead of the whole word.

Thanks.

http://wordpress.org/extend/plugins/wp-simple-galleries/