Reduce caption box around image

Hello Richie & other users,

I want to reduce the size of the box that surrounds an image in my posts. I have used the current CSS to reduce the font size and remove the grey background of the box:

#custom .wp-caption {box-shadow: none;background-color: transparent;}
#custom .wp-caption .wp-caption-text {padding: 10px;font-size: 11px;line-height: 15px;}
#custom .wp-caption .wp-caption-text:before {content: ”;}

However the space between the caption and the body content is pretty big. Do you know how to reduce it?

To show you the example; my website is https://northamptongent.com/a-taste-of-the-mediterranean-nuovo-restaurant/

Any help would be much appreciated!