<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style>
    p {
        font-size: 20px;
        position: relative;
        z-index: 0;
        color: #fff;
    }
    p::before,
    p::after {
        content: attr(data-text);
        position: absolute; left: 0;
        z-index: -1;
    }
    p::before {
        -webkit-text-stroke: 6px blue;
    }
    p::after {
        -webkit-text-stroke: 4px blue;
    }
  </style>
</head>
<body>
  <div class="box">
      <p class="p1" data-text="外描边">
          外描边
      </p>
  </div>
</body>
</html>