What exactly qualifies as "generalized CSS?"
This would be a CSS rule that is applied to all instances of a particular HTML element, such as a div.
For example, something like:
... will apply to all divs on your web page (including those in your Juicebox gallery), whereas:
#sample {
display: none;
}
... will apply only to the div with id="sample".
It sounds like your theme may be the root of the probem. Please let me know whet theme you used so that I can investigate further.
And the transparent background for the gallery doesn't seem to change no matter what I do.
Your gallery currently used the following code:
backgroundColor: '#222222'
Change this to:
backgroundColor: 'rgba(0,0,0,0)'
The 4th parameter of the rgba expression (the alpha channel) is the opacity of the background (0 being transparent and 1 being opaque). If you use a 6-digit hexadecimal code rather than an rgba expression, the gallery's background will be opaque.
If using JuiceboxBuilder-Lite to create or edit your gallery, set the opacity of your gallery's background color to 0 on the 'Customize' tab.