<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <div class="box">
    我是父文本xx

    <span class="small">xx文字变大xx</span>
    <span class="small2">xx文字不在行内块中居中x</span>
    xx我是父文本
  </div>
</body>

</html>
.box {
  height: 100px;
  line-height: 100px;
  background-color: orange;
  font-size: 16px;
  color: white;
}

.box .small {
  display: inline-block;
  background-color: #f00;
  height: 80px;
  line-height: 80px;
  font-size: 50px;
}
.box .small2 {
  display: inline-block;
  background-color: blue;
  height: 80px;
  line-height: 130px;
  font-size: 16px;
}

External CSS

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External JavaScript

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