.button_top {
    position: fixed;
    right: 1rem;
    bottom: 1rem;
    width: 4rem;
    height: 4rem;
    border-radius: 100%;
    background: rgb(236, 160, 28) url(images/icons/white_arrow.png) center no-repeat;
    opacity: 1;
  }
  /* .button_top:hover {
    opacity: 0.8;
  }
  .button_top:focus {
    opacity: 0.9;
  } */
  .button_top:active {
    opacity: 1;
  }

img{
    width: 100%
}