The Style Settings can be found under the gallery’s settings. Go to Modula > Galleries > edit a gallery > scroll down to ‘Style’.

Border Size: set the border size of your images in the gallery (in pixels). It will be the same around each thumbnail image. It won’t be applied to images in the lightbox. Click here to see a demo.
Border Radius: set the border radius for your images (px). Click here to see a demo.
Border Color: set the color of your images’ borders in this gallery. Click here to see a demo.
Shadow Size: set the size of images’ shadows in the gallery (pixels). Click here to see a demo.
Shadow Color: set the shadow color. Click here to see a demo.