Bootstrap CSS - 更改为默认颜色在移动设备上不起作用 - 在桌面设备上正常

Question

我正在使用 CSS 构建我的第一个站点（www.craigdoesdata.de 如果你想看到这个问题的实际效果），如果这是显而易见的或已经得到回答（尽管我找了很久都没找到答案）。

我正在使用 Bootstrap 并在我的 custom.css 文件中为 .bg-dark 调整了 background-color，如下所示：

.bg-dark {
    background-color: #21618c !important;
}

这适用于桌面，导航栏和页脚等发生变化。但是在移动设备上会出现默认的 bg-dark 颜色 (#343a40)。当我检查它们指向 _background-variant.scss 的元素时，它仍然指定：

.bg-dark {
    background-color: #343a40 !important;
}

我的 custom.css 在 html 的 header 中最后加载，我认为这意味着它具有优先权，这在桌面上确实有效。但是，这里一定有我遗漏的东西，这意味着移动版本没有使用我的 custom.css 样式表？

这是我写的HTML：

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

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/css/bootstrap.min.css" integrity="sha384-9aIt2nRpC12Uk9gS9baDl411NQApFmC26EwAOH8WgZl5MYYxFfc+NcPb1dKGj7Sk" crossorigin="anonymous">

    <!-- Add icon library -->
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">

    <!-- Custom CSS -->
    <link rel="stylesheet" type="text/css" href="css/custom.css">

    <title>Craig Does Data | About</title>

  </head>

  <body>

    <!-- Start Navigation -->

      <nav class="navbar fixed-top navbar-expand-lg navbar-dark bg-dark fixed-top"> 

        <!-- Start Container -->
        <div class="container">

            <!-- Nav Brand -->
            <a class="navbar-brand" href="index.html">
              <img src="img/logo/logo w on blue.png" alt="The logo for Craig Does Data" height="40">
            </a>

            <!-- Start Button -->
            <button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbarResponsive" aria-controls="navbarResponsive" aria-expanded="false" aria-label="Toggle Navigation">
              <span class="navbar-toggler-icon"></span>
            </button>
            <!-- End Button -->


            <!-- Start Links -->
            <div class="collapse navbar-collapse" id="navbarResponsive">
              <ul class="navbar-nav ml-auto">

                <!-- Home -->
                <li class="nav-item">
                  <a class="nav-link" href=index.html>Home</a>
                </li>

                <!-- Services -->
                <li class="nav-item">
                  <a class="nav-link" href=blog.html>Blog</a>
                </li>

                <!-- Portfolio -->
                <li class="nav-item">
                  <a class="nav-link" href=projects.html>Projects</a>
                </li>

                <!-- About -->
                <li class="nav-item">
                  <a class="nav-link" href=about.html>About</a>
                </li>

                <!-- Contact -->
                <li class="nav-item">
                  <a class="nav-link" href=contact.html>Contact</a>
                </li>

              </ul>
            </div>
            <!-- End Links -->

        </div>
      </nav>
    <!-- End Navigation -->


    <!-- Start Container -->
    <div class="container">


    </div>
    <!-- End Container -->

<br>

    <!-- Footer -->
    <footer class="py-5 bg-dark">  
      <div class="container">
        <p class="m-0 text-center text-white">Copyright &copy; Craig Dickson 2020</p>
        <!--Twitter-->
        <div align="center">
        <a href="http://www.twitter.com/craigdoesdata" target="_blank" class="fa fa-twitter"></a>
        <!--GitHub-->
        <a href="https://github.com/thecraigd" target="_blank" class="fa fa-github"></a>
        <!--Medium-->
        <a href="https://medium.com/@thecraigdickson" target="_blank" class="fa fa-medium"></a>
        <!--LinkedIn-->
        <a href="https://www.linkedin.com/in/dicksoncraig/" target="_blank" class="fa fa-linkedin"></a>
      </div>
      </div>

    </footer>

    <!-- Optional JavaScript -->
    <!-- jQuery first, then Popper.js, then Bootstrap JS -->
    <script src="https://code.jquery.com/jquery-3.5.1.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
    <script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js" integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo" crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/js/bootstrap.min.js" integrity="sha384-OgVRvuATP1z7JjHLkuOU7Xw704+h835Lr+6QL9UvYjZE3Ipu6Tp75j7Bh/kR0JKI" crossorigin="anonymous"></script>
  </body>
</html>

这里是custom.css

/* Start Global Styles */

body {
    padding: 1em;
}

@media (min-width: 992px) {
    body{
        padding-top: 56px;
}

.carousel-item {
    height: 65vh;
    min-height: 300px;
    background: no-repeat center center scroll;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
}

.portfolio-item {
    margin-bottom:30px;
}

/* End Global Styles */

/* My colour palette (from htmlcolorcodes.com) */
/* color-4 is my primary, color-3 for hovers */
.color-1 {color: #d2b4de;}
.color-2 {color: #5b2c6f;}

.color-3 {color: #aed6f1;}
.color-4 {color: #21618c;}

.color-5 {color: #76d7c4;}
.color-6 {color: #117864;}


/* Navigation Background Colour */

.bg-dark {
    background-color: #21618c !important;
}

/* Call to Action ('Contact me' on index.html) Button State */

.btn-secondary {
    color: #fff;
    background-color: #21618c;
    border-color: #21618c;
}

.btn-secondary:hover {
    color: #fff;
    background-color: #5499c7;
    border-color: #5499c7;
}

/* Button Hover State */

.btn-primary:hover {
    color: #fff;
    background-color: #5499c7;
    border-color: #5499c7;
}

/* Button normal state */
.btn-primary {
    color: #fff;
    background-color: #21618c;
    border-color: #21618c;
}


/* Nav Link Colour */

.navbar-dark .navbar-nav .nav-link:focus, .navbar-dark .navbar-nav .nav-link:hover {
    color: white;
}
.navbar-dark .navbar-nav .nav-link {
    color: black;
}

在此先感谢您的帮助！

Answer 1

您在媒体查询中拥有样式。例如，看看我在检查您的网站时得到的这个。此处正在使用媒体查询

@media (min-width: 992px)
.btn-secondary {
    color: #fff;
    background-color: #21618c;
    border-color: #21618c;
}

因此，当设备宽度低于 992px 时，它会采用默认颜色值，而不是您在 custom.css.

中指定的覆盖值

Bootstrap CSS - 更改为默认颜色在移动设备上不起作用 - 在桌面设备上正常

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