<html>
<head>
<meta http-equiv="Content-Type"content="text/html; charset=utf-8"/>
<style>
blockquote, body, button, dd, dl, dt, fieldset, form, h1, h2, h3, h4, h5, h6, hr, input, legend, li, ol, p, pre, td, textarea, th, ul{
margin: 0;
padding: 0;
}
h3 {
display: block;
margin: 0;
padding: 0;
}
.cat {
position: relative;
width: 150px;
background: #f8f8f8;
border: 1px solid #bbb;
}
ol, ul {
list-style: none;
}
li {
z-index: 2;
position: relative;
display: block;
height: 31px;
line-height: 31px;
overflow: hidden;
margin: 1px 10px 0;
vertical-align: bottom;
border-bottom: 1px solid #dedede
}
li h3 {
font-size: 14px;
font-weight: 400;
}
li i {
display: inline;
float: left;
margin: 3px 10px 0 0;
height: 24px;
width: 30px
background:url(http://img.mukewang.com/539a950e00015ba500710200.jpg);
}
/* 在这里补充雪碧图的样式 */
.cat-1 i{background-position:0 0;}
.cat-2 i{background-position:0 -24px;}
.cat-3 i{background-position:0 -48px;}
.cat-4 i{background-position:0 -72px;}
.cat-5 i{background-position:0 -96px;}
.cat-6 i{background-position:0 -120px;}
.cat-7 i{background-position:0 -144px;}
.cat-8 i{background-position:0 -168px;}
</style>
</head>
<body>
<div class="cat">
<ul >
<li class="cat-1">
<i></i>
<h3>服装内衣</h3>
</li>
<li class="cat-2">
<i></i>
<h3>鞋包配饰</h3>
</li>
<li class="cat-3">
<i></i>
<h3>运动户外</h3>
</li>
<li class="cat-4">
<i></i>
<h3>珠宝手表</h3>
</li>
<li class="cat-5">
<i></i>
<h3>手机数码</h3>
</li>
<li class="cat-6">
<i></i>
<h3>家电办公</h3>
</li>
<li class="cat-7">
<i></i>
<h3>护肤彩妆</h3>
</li>
<li class="cat-8">
<i></i>
<h3>母婴用品</h3>
</li>
</ul>
</div>
</body>
</html>
li i {
display: inline;
float: left;
margin: 3px 10px 0 0;
height: 24px;
width: 30px; /**这里少了分号**/
background:url(http://img.mukewang.com/539a950e00015ba500710200.jpg);
}上面一个不对，因为有float 所以 display: inline; 就没什么用了。
浮动的影响
li i {
display: inline; /**这里的inline改成 inline-block 试试**/
float: left;
margin: 3px 10px 0 0;
height: 24px;
width: 30px
background:url(http://img.mukewang.com/539a950e00015ba500710200.jpg);
}