Issues with Back to Top scrolling button

Site URL: http://www.dandelion-drum-w9ws.squarespace.com

I entered code to get my "back-to-top button in place, and there is a weird overlap, rather than the image laying perfectly over the button. 

Here's the css I have entered:

#back-to-top{
  height:45px;
  width:45px;
  position:fixed;
  padding:9px;
  bottom:0;
  right:0;
  z-index:99;
  
  border-radius:100%;
  box-shadow: 0px 0px 5px #ccc;
  margin:20px;
  background:white;
}

html{
  scroll-behavior:smooth;
}

And this is the code I've injected in the header:

<div id="scroll-here"></div>
<a id="back-to-top" href="#scroll-here">
  <img src="https://static1.squarespace.com/static/61f41cf600dec14c7c38f90b/t/62542758a81ed506e7f2b164/1649682264925/arrow-up-circle-52_989ac618-1138-4d30-9b85-aee2cc99139e.png">
</a>

My testing

Oh my goodness, thank you so much for your help with this, it worked perfectly : ) I apologize for the delay on responding, I did't see your comment until just now. Many thanks for your assistance!!!

Hi!

It worked on my desktop, but there's an overlap on the mobile end.

On 5/17/2022 at 9:21 AM, SupremePT said:

Hi!

It worked on my desktop, but there's an overlap on the mobile end.

Which overlap? Can you take a screenshot + link to your site, we can help easier