*{
	margin: 0px;
	padding: 0px;
}
.big{
	width: 500px;
	height: 300px;
	margin: 10px auto;
	position: relative;/*参照物*/
}
.pic{
	width: 500px;
	height: 300px;
	border: 1px solid #464646;
}
.pic img{
	position: absolute;/*绝对定位*/
	display: none;
}
.arr{
	width: 40px;
	height: 70px;
	font-size: 30px;
	font-weight: 900;
	line-height: 70px;
	text-align: center;
	color: #ccc;
	position: absolute;
	top: 125px;
	display: none;
	cursor: pointer;
}
.l-arr{
	left: 0px;
}
.r-arr{
	right: 0px;
}
.big:hover .arr{
	display: block;
}
.arr:hover{
	background: rgba(0,0,0,0.3);
	color: #fff;
}
.but{
	position: absolute;
	bottom: 15px;
	right: 12px;
}
.but ul li{
	list-style-type: none;
	width: 30px;
	height: 20px;
	/*border: 1px solid #ccc;*/
	float: left;
	margin-left: 10px;
	text-align: center;
	font-family: "microsoft yahei";
	line-height: 20px;
	font-size: 12px;
	color: #fff;
	background: rgba(0,0,0,0.3); 
	cursor: pointer;
}
.but ul li:hover{
	background:rgba(0,0,0,0.7);
}
.but .hover{
	background:rgba(0,0,0,0.7);
}