CSS邊框內數(shù)字居中方法

在CSS中，要使邊框內的數(shù)字居中，可以使用多種方法，***常用的是使用flexbox布局，下面是一個簡單的示例：

HTML代碼：

<div class="container">
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="item">1234567890</div>
  <div class="