.up-btn {
  width: 50px;
  height: 50px;
  right: 20px;
  bottom: 20px;
  opacity: .7;
  background:transparent;
  cursor: pointer;
  position: fixed;
  z-index: 2000;
  transition: all .4s ease-in-out;
  padding: 10px;
  box-sizing: border-box;
  display: flex;
  justify-content: center;
  align-items: center;
  transform: scale(1);
}

.up-btn.up-btn__hide {
  opacity: 0;
  transform: scale(0);
  transition: all .4s ease-in-out;
}

.up-btn:hover {
  opacity: 1;
}

.up-btn.up-btn_circle {
  border-radius: 50%;
}

.up-btn__img {
  width: 100%;
  max-width: 100%;
}

#return-to-top {
  position: fixed;
  bottom: 100px;
  right: 20px;
  background: rgb(119, 161, 64);
  background: rgba(119, 161, 64, 0.7);
  width: 50px;
  height: 50px;
  display: block;
  text-decoration: none;
  -webkit-border-radius: 35px;
  -moz-border-radius: 35px;
  border-radius: 35px;
  display: none;
  -webkit-transition: all 0.3s linear;
  -moz-transition: all 0.3s ease;
  -ms-transition: all 0.3s ease;
  -o-transition: all 0.3s ease;
  transition: all 0.3s ease;
  z-index:99999999999999999999999999;
}

.hide{
  visibility:hidden;
}

.show{
  display:block;
}
#return-to-top i {
    color:black;
    margin: 0;
    position: relative;
    left: 16px;
    top: 13px;
    font-size: 19px;
    -webkit-transition: all 0.3s ease;
    -moz-transition: all 0.3s ease;
    -ms-transition: all 0.3s ease;
    -o-transition: all 0.3s ease;
    transition: all 0.3s ease;
}
#return-to-top:hover {
    background: rgba(119, 161, 64, 0.9);
}
#return-to-top:hover i {
    color: #fff;
    top: 5px;
}