.gototop{
  position: fixed;
  display: block;
  box-sizing: border-box;

  border: none;
  background-color: #333;
  border-radius: 3px;
  margin-right: -30px;
  outline: none;
  opacity: 0;
  transition: opacity .3s ease, margin-right .5s ease-out;
  cursor: pointer;
  z-index:3000;
}

@media screen and (min-width: 601px) {
  .gototop {
    height: 50px;
  	width: 50px;
	bottom: 70px;
  	right: 50px;
  }
  .gototop::before, .gototop::after{
  content: '';
  position: absolute;
  height: 18px;
  width: 2px;
  background-color: #fff;
  top: 16px;
}
  .gototop::before{
	left: 18px;
	transform: rotate(45deg);
  }
  .gototop::after{
	right: 18px;
	transform: rotate(-45deg);
  }
}
@media screen and (max-width: 600px) {
   .gototop {
  	height: 39px;
  	width: 39px;
	bottom: 30px;
  	right: 30px;
	}
	.gototop::before, .gototop::after{
	content: '';
	position: absolute;
	height: 14px;
	width: 1px;
	background-color: #fff;
	top: 12px;
  }
  .gototop::before{
	left: 14px;
	transform: rotate(45deg);
  }
  .gototop::after{
	right: 14px;
	transform: rotate(-45deg);
  }
}
 
.visible{
  transition: opacity .3s ease, margin-right .5s ease-out;
  margin-right: 0px;
  opacity: .6;
}