a		{
		 background: url(button.gif) no-repeat;
		 float: left;
		 text-align: center;
	 	 width: 300px;
		 height: 100px; 
		 line-height: 100px;
		 text-decoration: none;
		 margin: 0 auto;
		 color: #000000;
		 font-weight: bold;
		 }
		 
a:hover {
		 background: url(button.gif) left bottom;
		 width: 300px;
		 height: 100px;
		 color: #FF0000;
		 }