Why isnt my image being sticky?

Site URL: http://www.dolphinbottles.co.uk

Hi,

website pw: dolphin

Hope image helps explain too. I want the logo in bottom right to follow users as they scroll.

Current image is a coded image: 

<img src="https://static1.squarespace.com/static/5efca1d4b38d327351cb3a48/t/5f80623086feca1a363d3f95/1602249265109/Untitled+design+%288%29+%281%29.png" style="float:right;width:12%;height:12%;" "class="stickydolphin">

with this in Custom CSS: 

.stickydolphin {
  position: sticky;
  right: 0;
}

What am I missing? Thank you 🙂