Help! Slideshow gallery displays tiny thumbnails on mobile

https://konishigaffney.squarespace.com/greyfriars-charteris-centre

Password: buildings

I'm happy with the gallery display on desktop, but on mobile the images become absolutely tiny! Can you help? I've removed all the code and there doesn't seem to be anything interfering with it. See below the only code I have:

#collection-65a7cee80a4862762028b14c .sqs-gallery  {
  max-height: calc(100vh - 30px) !important;
}

#collection-65a7cee80a4862762028b14c .slide img {
  height: 100% !important;
  width: auto !important;
   left: 50% !important;
   transform: translateX(-50%);
}
#collection-65a7cee80a4862762028b14c .slide {
  height: 100% !important;
}

.sqs-gallery-controls .previous {
  color: #120E25 !important;
  font-size: 10px !important;
  line-height: 10px !important;
  background-color: transparent !important;
  padding: 0px !important;
}

.sqs-gallery-controls .next {
  color: #120E25 !important;
  font-size: 10px !important;
  line-height: 10px !important;
  background-color: transparent !important;
  padding: 0px !important;
}

I've attached mobile screenshots so you can see. Ideally, the images would be at least full width. Happy for the controls to be moved to below or a background colour added for extra visibility.