无法使用标签选择器更改 css 中的元素属性

如何解决无法使用标签选择器更改 css 中的元素属性

我是 Web 开发领域的新手，我参加了 Angela Yu 的 Web 开发训练营。我目前正在使用 bootstrap v5、html5、CSS3

我遇到了一个问题，当我使用标签选择进行定位时，我无法更改 body 标签的属性

这是我的 index.html

(get-date).AddDays(3).ToString() | Out-File -FilePath time.txt
$deadline = [datetime](Get-Content -Path time.txt) 
$currenttime = Get-Date
IF ($currenttime -lt $deadline) {Write-host "Continue Working"} Else  {Write-Host "Your Logic is Wrong"}

这是我的Styles.css

<!DOCTYPE html>
<html>

<head>
  <Meta charset="utf-8">
  <title>TinDog</title>

  <!-- External style Sheet -->
  <link rel="stylesheet" href="css/styles.css">

  <!-- bootstrap -->
  <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.0.0-beta3/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-eOJMYsd53ii+scO/bJGFsiCZc+5NDVN2yr8+0RDqr0Ql0h+rP48ckxlpbzKgwra6" crossorigin="anonymous">
  <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.0.0-beta3/dist/js/bootstrap.bundle.min.js" integrity="sha384-JEW9xMcG8R+pH31jmWH6WWP0WintQrMb4s7ZOdauHnUtxwoG2vI5DkLtS3qm9Ekf" crossorigin="anonymous"></script>
  <!-- Google fonts -->
  <link rel="preconnect" href="https://fonts.gstatic.com">
  <link href="https://fonts.googleapis.com/css2?family=Montserrat&family=Ubuntu:wght@500&display=swap" rel="stylesheet">
  <!-- font awesome -->
  <link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.15.3/css/all.css" integrity="sha384-SZXxX4whJ79/gErwcOYf+zWLeJdY/qpuqC4cAa9rOGUstPomtqpuNWT9wdPEn2fk" crossorigin="anonymous">
</head>

<body>
  <section id="title">
    <!-- Nav Bar -->
    <nav class="navbar navbar-expand-lg navbar-dark">
      <div class="container-fluid p-0 title-container">
        <a href="#" class="navbar-brand">tinCat</a>
        <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
          <span class="navbar-toggler-icon"></span>
        </button>
        <div class="collapse navbar-collapse justify-content-end" id="navbarSupportedContent">
          <ul class="nav navbar-nav">
            <li class="nav-item"><a class="nav-link" href="">Contact</a></li>
            <li class="nav-item"><a class="nav-link" href="">Pricing</a></li>
            <li class="nav-item"><a class="nav-link" href="">Download</a></li>

          </ul>
        </div>
      </div>

    </nav>
    <!-- Nav Bar end -->


    <!-- Download Section -->
    <div class="container-fluid p-0 title-things">
      <div class="row">
        <div class="col-lg-6 ">
          <h1>Meet new and interesting cats nearby.</h1>
          <button type="button" class="btn btn-light download-button"><i class="fab fa-apple"></i> Download</button>
          <button type="button" class="btn btn-dark download-button"><i class="fab fa-google-play"></i> Download</button>
        </div>
        <div class="col-lg-2">
          <img class="cat-profile"src="images/iphone6.png" alt="iphone-mockup">
        </div>
      </div>

  </section>
  </div>



</body>

</html>

相反我在标签中添加了一个新类，在外部样式表中，我使用类选择器将它作为目标并且它起作用了！有人能解释一下原因吗？

解决方法

这完全取决于您的样式出现的顺序，因此如果您在 bootstrap 下方添加样式，它将覆盖 bootstrap 样式。像这样更改代码，

        <!-- bootstrap -->
        <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.0.0-beta3/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-eOJMYsd53ii+scO/bJGFsiCZc+5NDVN2yr8+0RDqr0Ql0h+rP48ckxlpbzKgwra6" crossorigin="anonymous">
        <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.0.0-beta3/dist/js/bootstrap.bundle.min.js" integrity="sha384-JEW9xMcG8R+pH31jmWH6WWP0WintQrMb4s7ZOdauHnUtxwoG2vI5DkLtS3qm9Ekf" crossorigin="anonymous"></script>
        <!-- Google fonts -->
        <link rel="preconnect" href="https://fonts.gstatic.com">
        <link href="https://fonts.googleapis.com/css2?family=Montserrat&family=Ubuntu:wght@500&display=swap" rel="stylesheet">
        <!-- font awesome -->
        <link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.15.3/css/all.css" integrity="sha384-SZXxX4whJ79/gErwcOYf+zWLeJdY/qpuqC4cAa9rOGUstPomtqpuNWT9wdPEn2fk" crossorigin="anonymous">

       <!-- External style Sheet -->
      <link rel="stylesheet" href="css/styles.css">

将您的样式表放在其他样式表之下

          <head>
            <meta charset="utf-8">
            <title>TinDog</title>

            <!-- bootstrap -->
            <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.0.0-beta3/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-eOJMYsd53ii+scO/bJGFsiCZc+5NDVN2yr8+0RDqr0Ql0h+rP48ckxlpbzKgwra6" crossorigin="anonymous">
            <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.0.0-beta3/dist/js/bootstrap.bundle.min.js" integrity="sha384-JEW9xMcG8R+pH31jmWH6WWP0WintQrMb4s7ZOdauHnUtxwoG2vI5DkLtS3qm9Ekf" crossorigin="anonymous"></script>
            <!-- Google fonts -->
            <link rel="preconnect" href="https://fonts.gstatic.com">
            <link href="https://fonts.googleapis.com/css2?family=Montserrat&family=Ubuntu:wght@500&display=swap" rel="stylesheet">
            <!-- font awesome -->
            <link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.15.3/css/all.css" integrity="sha384-SZXxX4whJ79/gErwcOYf+zWLeJdY/qpuqC4cAa9rOGUstPomtqpuNWT9wdPEn2fk" crossorigin="anonymous">

          <!-- External style Sheet -->
          <link rel="stylesheet" href="css/styles.css">
          </head>