Topic: The main image should not be smashed up against the top of the window

The main image should not be smashed up against the top of the browser window. It looks like perhaps the top of the image has been accidentlaly cut off. It looks visually crowded. Please add a

padding-top: 0.5rem

to give a tiny amount of breathing room up top.

Re: The main image should not be smashed up against the top of the window

You can set some space around the main image using imagePadding (in JuiceboxBuilder-Pro's 'Customize -> Main Image' section) or around the gallery itself using stagePadding ('Customize -> General').
Both of these configuration options have default values of 0 (and values are in pixels).