*{padding: 0;margin: 0;}

   #myBtn {

     display: none;

     position: fixed;

     bottom: 3px;

     right: 3px;

     z-index: 99;

     border: none;

     outline: none;

     background-color: skyblue;

     color: white;

     cursor: pointer;

     padding: 15px;

     border-radius: 10px;

   }

    

   #myBtn:hover {

     background-color: plum;

   }