How to change Lightbox overlay font

Site URL: http://hannahpeckillustration.co.uk

I'd like to change this hover / overlay Lightbox font: 

to match the font I have before clicking (Adobe Calson Pro): 

I've checked my global style texts and they're all serif, so unsure where this is coming from. 

Any CSS I can stick on the end?

thanks 

Hey @hpeck try to add next code in Custom CSS:

.yui3-lightbox2 .sqs-lightbox-meta p {
  font-family: minion-pro;
}