.back {
    position: fixed;
    bottom: 20px;
    right: 20px;
    height: 50px;
    width: 50px;
    border-radius: 50%;
    line-height: 3rem;
    color: #511f52;
    background-color: #a987a8;
    /* display: none; */
    justify-content: center;
    text-align: center;
    align-items: center;
    font-weight: bolder;
    cursor: pointer;
    display: none;
    /* box-shadow: 2px 2px 5px 2px #fff; */
    animation: fade_in_button .5s ease;
    z-index: 10;
  }

  .button_active{
    display: block;
  }
  
  .back:hover {
    transform: scale(1.1);
    /* color: #01134d; */
    background-color: #ecd4ea;
    transition: 0.6s;
  }
  
  @keyframes fade_in_button {
    0% {
      transform: scale(0);
    }
  
    100% {
      transform: scale(1);
    }
  }