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首页 > 解决方案 > 为什么 mt-3 [mb-3] 没有应用于引导程序中的每一行？

html - 为什么 mt-3 [mb-3] 没有应用于引导程序中的每一行？

问题描述

我有两行，想在顶部和底部添加一些空间。所以我添加了属性 mt-3 和 mb-3。但这些属性似乎只适用于第一行。

我怎样才能将它们应用到每一行？

<!doctype html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" integrity="sha384-WskhaSGFgHYWDcbwN70/dfYBj47jz9qbsMId/iRN3ewGhXQFZCSftd1LZCfmhktB" crossorigin="anonymous">
</head>
<body>
    <div class="row mt-3 mb-3" style="background-color:white">
        <div class="col-3">
            completions based on variable types, function definitions, and imported modules.
        </div>
        <div class="col-3">
            completions based on variable types, function definitions, and imported modules.
        </div>
        <div class="col-3">
            completions based on variable types, function definitions, and imported modules.
        </div>
        <div class="col-3">
            completions based on variable types, function definitions, and imported modules.
        </div>
    </div>

    <div class="row mt-3 mb-3" style="background-color:whitesmoke">
        <div class="col-3">
            completions based on variable types, function definitions, and imported modules.
        </div>
        <div class="col-3">
            completions based on variable types, function definitions, and imported modules.
        </div>
        <div class="col-3">
            completions based on variable types, function definitions, and imported modules.
        </div>
        <div class="col-3">
            completions based on variable types, function definitions, and imported modules.
        </div>
    </div>

    <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js" integrity="sha384-smHYKdLADwkXOn1EmN1qk/HfnUcbVRZyYmZ4qpPea6sjB/pTJ0euyQp0Mk8ck+5T" crossorigin="anonymous"></script>
</body>
</html>

标签： htmltwitter-bootstrap

解决方案

您所拥有的称为保证金崩溃：

...当两个元素的垂直边距接触时，只有边距值最大的元素的边距将被尊重，而边距值较小的元素的边距将被折叠为零。

本质上，边距应用于两个元素，但边距重叠。

要解决此问题，您有三个选择：

  • float: left
  • position: absolute
  • display: inline-block

最简单的解决方案（在我看来）是简单地应用于float: left有问题的元素：

.mt-3, .mb-3 {
  float: left;
}
<!doctype html>
<html lang="en">

<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

  <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" integrity="sha384-WskhaSGFgHYWDcbwN70/dfYBj47jz9qbsMId/iRN3ewGhXQFZCSftd1LZCfmhktB" crossorigin="anonymous">
  <link href="styles.css" rel="stylesheet" />

  <title>Web-UI-Automation</title>
</head>

<body>
  <div class="row mt-3 mb-3" style="background-color:white">
    <div class="col-3">
      completions based on variable types, function definitions, and imported modules.
    </div>
    <div class="col-3">
      completions based on variable types, function definitions, and imported modules.
    </div>
    <div class="col-3">
      completions based on variable types, function definitions, and imported modules.
    </div>
    <div class="col-3">
      completions based on variable types, function definitions, and imported modules.
    </div>
  </div>

  <div class="row mt-3 mb-3" style="background-color:whitesmoke">
    <div class="col-3">
      completions based on variable types, function definitions, and imported modules.
    </div>
    <div class="col-3">
      completions based on variable types, function definitions, and imported modules.
    </div>
    <div class="col-3">
      completions based on variable types, function definitions, and imported modules.
    </div>
    <div class="col-3">
      completions based on variable types, function definitions, and imported modules.
    </div>
  </div>

  <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
  <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js" integrity="sha384-smHYKdLADwkXOn1EmN1qk/HfnUcbVRZyYmZ4qpPea6sjB/pTJ0euyQp0Mk8ck+5T" crossorigin="anonymous"></script>
</body>

</html>

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