固定的盒子需要絕對定位才能達到以下效果，希望有不需要絕對定位實現以下方法的大神！求指點
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
html,
body {
height: 100%;
padding: 0;
margin: 0;
overflow: hidden;
}
.outer {
height: 100%;
padding: 100px 0 0;
box-sizing: border-box;
}
.A {
height: 100px;
background: #BBE8F2;
position: absolute;
top: 0;
left: 0;
width: 100%;
}
.B {
height: 100%;
background: #D9C666;
overflow: scroll;
}
</style>
</head>
<body>
<p class="outer">
<p class="A"> 头部p </p>
<p class="B">
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdfD</p> <p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdfD</p> <p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdfD</p> <p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdfD</p> <p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdfD</p> <p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdfD</p> <p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>abcabsdf</p>
<p>sssssssssssssssssssssss</p>
</p>
</p>
</body>
</html>
問題有點模糊，如果是要求A+B等於outer的高度，可以用
calc(100% - 100px);浮動 固定定位
你的問的不太明白啊，能說的具體點嗎？