导航链接添加背景图片替换样式

<div class="welcome_button">
　　<ul>
	<li><a href="#">signup</a></li>
	<li><a href="#">login</a></li>								
　　</ul>
</div>

<style type="text/css">
.welcome_button
{
	text-align: center;
}
.welcome_button ul
{
	list-style:none;
	padding-top: 12px;
	padding-left: 130px;
}

.welcome_button ul li
{
	background:url(../img/welcome_button.jpg) no-repeat top center;
	width:190px;
	height:56px;
	text-align: center;
	line-height: 50px;
	margin-top:30px;
}
.welcome_button ul li a
{
	color: #ffffff;
	display:block;
	text-decoration: none;
}
.welcome_button ul li a:hover
{
	background:url(../img/welcome_button_hover.jpg) no-repeat;
	width:190px;
	height:56px;
	text-align: center;
	line-height: 50px;
	color: #fff;
}
</style>