Can I add a button under a simple slide show section in Squarespace 7.1 with code

Site URL: https://www.mollieart.com/

Hi, is it possible to add a button under a simple slide show section in Squarespace 7.1 with code? I want to add a button under the descriptions but in the same section. If I make a new section the spacing is too big even if I code the padding to be minimal around the section. Thanks. Hope I am making sense. I have mocked up an image below of where I would like the button. Thanks. 🙂

My password is 

james

Edit Gallery Slideshow Image >> In Description box >> enter this code under current description

<a class="slideshow-button">Button text</a>

next, add this to Design > Custom CSS

a.slideshow-button {
	border: 2px solid black;
	padding: 20px 30px;
}

If it doesn't work, please keep the code & let me know, we will try checking again