add a border to product detail page

@Barbi Give this a go - paste in your custom CSS panel:

// main product image //
.tweak-product-basic-item-gallery-design-slideshow .ProductItem-gallery-slides-item {
  border: 2px solid hotpink;
  box-sizing: border-box;
  box-shadow: 0 0 6px 0px hotpink !important;
  width: 98%;
  height: 98%;
  margin-left: 1%;
  margin-top: 1%;
}

// product thumbnail //
.ProductItem-gallery-thumbnails-item img {
  border: 2px solid hotpink;
  box-sizing: border-box;
  box-shadow: 0 0 6px 0px hotpink !important;
}

It's probably not perfect with the glow around the border radius but here's what this looks like on my end: