#backtotop {
  background: /*pink*/ url(../images/backtotop.png) no-repeat center center;
  border: 0;
  bottom: 20px;
  cursor: pointer;
  display: none;
  height: 70px;
  position: fixed;
  right: 20px;
  text-indent: -9999px;
  width: 70px;
  z-index: 1;
}

#backtotop:hover {
  background: /*orange*/ url(../images/backtotop-hover.png) no-repeat center center;
}

#backtotop:hover {
  opacity: 0.8;
}

#backtotop:focus {
  opacity: 0.6;
  outline: none;
}

@media	screen 
		and (min-device-width: 1200px) 
		and (max-device-width: 1600px)
		and (-webkit-min-device-pixel-ratio: 2),
		and (min-resolution: 192dpi) {
  #backtotop {
    background: /*aqua*/ url(../images/backtotop2x.png) no-repeat center center;
    background-size: 70px 70px;
  }

  #backtotop:hover {
    background: /*lime*/ url(../images/backtotop2x-hover.png) no-repeat center center;
    background-size: 70px 70px;
  }
}

@media print {
  #backtotop {
    visibility: hidden;
  }
}