纯css实现吸顶效果

<div class="header">

</div>
<nav>
    用于显示粘性定位的头
</nav>
<div class="content">

</div>
<footer>
    底部
</footer>

.header {
	width:100%;
	height:160px;
	background:#87CEEB;
}
nav {
	width:100%;
	height:100px;
	position:sticky;
	top:0px;
	background:#F98202;
}
.content {
	width:100%;
	background:blue;
	height:1000px;
}
footer {
	background:#87CEEB;
}