#back-to-top{
		position:fixed;
		bottom:5%;
		left:90%;
	}
	#back-to-top a{
		text-align:center;
		text-decoration:none;
		color:#d1d1d1;
		display:block;
		width:50px;
		/*ʹ��CSS3�е�transition���Ը���ת�����е�������ӽ���Ч��*/
		-moz-transition:color 1s; 
		-webkit-transition:color 1s;
		-o-transition:color 1s;
	}
	#back-to-top a:hover{
		color:#979797;
	}
	#back-to-top a span{
		display:block;
		height:50px;
		width:50px;
		background:url(img/top.png) no-repeat center center;
		margin-bottom:5px;
		-moz-transition:background 1s;
		-webkit-transition:background 1s;
		-o-transition:background 1s;
	}
	#back-to-top a:hover span{
		background:url(img/top.png) no-repeat center center;
	}