#myBtn {
    display: none;
    position: fixed;
    bottom: 50px;
    right: 30px;
    z-index: 99;
    font-size: 18px;
    border: none;
    outline: none;
    background-image: url("img/btt.png");
    color: white;
    cursor: pointer;
    padding: 15px;
    border-radius: 4px;
    height: 70px;
    width:70px;
  }
  
  #myBtn:hover {
    background-color: #333;
  }
#start{
  float: right;
  text-align: center;
  background-color:rgb(38, 39, 38);
  color: white;


}

#start:hover{
  background-color: tomato;
}