思路：
在原来的标签添加一个子集 <子绝父相>;
代码：
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport"
content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
.shadow-title {
text-align: center;
font-size: 22px;
height: 50px;
color: #fff;
width: 280px;
line-height: 50px;
position: relative;
background-color: #FEA001;
}
.shadow-title:after{
content: "";
position: absolute;
bottom: 5px;
right: 40px;
width: 75%;
height: 50%;
background-color: #bbb;
-moz-box-shadow: 0 0 10px 10px #bbb;
box-shadow: 0 0 10px 10px #bbb;
-ms-transform: skew(30deg, 4deg);
-moz-transform: skew(30deg, 4deg);
-webkit-transform: skew(30deg, 4deg);
-o-transform: skew(30deg, 4deg);
transform: skew(30deg, 4deg);
z-index: -1;
}
</style>
</head>
<body>
<div class="shadow-title">倾斜box-shadow</div>
</body>
</html>