Button with icon with absolute position and Off-canvas jumps in UIkit, how to fix it?

Question

css

Let me know if anyone has encountered the issue. It is necessary to make a button with an absolute position bottom right, it seemed to work, but there was a problem in combination with off-canvas. When opening off-canvas, the button moves up, can anyone know how to fix it?
https://codepen.io/bulat73/pen/pMgwxQ

Answer 1

body {
  min-height: 100vh;
}

and remove extra indents

Answer 2

ajax, examples in google are just heaps

Answer 3

https://api.jquery.com/jquery.post/