#slider {
  position: relative;
  overflow: hidden;
  margin:0 auto;
  border-radius: 4px;
  /* width:1680px; */
}

#slider ul {
  position: relative;
  margin: 0 auto;
  padding: 0 auto;
  list-style: none;
}

#slider ul li {
  position: relative;
  display: block;
  float: left;
  margin: 0;
  padding: 0;
  /* width:1680px; */
  background: #ccc;
  text-align: center;
  /* line-height: 400px; */
  height:800px;
}


#slider ul li img {
	position:relative;
	display:block;
/*	width:1680px; */
	}

a.ctrl_prev, a.ctrl_next {
  position: absolute;
  top: 40%;
  z-index: 999;
  display: block;
  padding: 4% 3%;
  width: auto;
  height: auto;
  background: #2a2a2a;
  color: #fff;
  text-decoration: none;
  font-weight: 600;
  font-size: 18px;
  opacity: 0.8;
  cursor: pointer;
}

a.ctrl_prev:hover, a.ctrl_next:hover {
  opacity: 1;
  -webkit-transition: all 0.2s ease;
}

a.ctrl_prev {
  border-radius: 0 2px 2px 0;
}

a.ctrl_next {
  right: 0;
  border-radius: 2px 0 0 2px;
}

.slider_option {
  position: relative;
  margin: 10px auto;
  width: 160px;
  font-size: 18px;
}



@media screen and (max-width: 640px) {
	.slider_option {
	  position: relative;
	  margin: 10px auto;
	  width: 30px;
	  font-size: 10px;
	}
	#slider ul li {
		height: 280px;
	}
a.ctrl_prev, a.ctrl_next {
  position: absolute;
  top: 46%;
  z-index: 999;
  display: block;
  padding: 1% 1%;
  width: auto;
  height: auto;
  background: #2a2a2a;
  color: #fff;
  text-decoration: none;
  font-weight: 600;
  font-size: 10px;
  opacity: 0.8;
  cursor: pointer;
}
}