body {
  height: 5000px;
  background: #E86357;
}
.up{
  position: fixed;
  bottom: 30px;
  right: -100px;
  background-color: #2C2D2A;
  color: white;
  font-weight: bold;
  font-size: 12px;
  padding:10px 15px;
  border-radius: 4px;
  font-family: Arial, Tahoma;
  cursor: pointer;
  transition: 0.5s;
}
.up:hover{
  background: #fff;
  color: #2C2D2A;
}
.up.show {
  right: 30px;
}