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<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
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<style>
.container{
width: 150px;
height: 100px;
background: blueviolet;
clip-path: polygon(25px 0,100% 0,100% 100%,0 100%,0 25px);
}
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<body>
<div class="container">
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原文：https://www.cnblogs.com/lmp5023/p/13291981.html