html, body { 
  margin: 0;
  overflow: hidden;
}

.btn {
    position: fixed;
    bottom: 5%;
    right: 0px;
    transform: translateX(-50%);
    border: 1px solid #fff;
    border-radius: 5px;
    font-size: 0.9rem;
    padding: 0.5rem 0.7em;
    background-color: transparent;
    color: #ffffff;
    font-family: Verdana, Geneva, Tahoma, sans-serif;
    -webkit-font-smoothing: antialiased;
    cursor: pointer;
    transition: all .3s;
    z-index: 11;
}