Bootstrap 3是否使用Flexbox

Bootstrap 3使用floats来处理布局，以取代flexbox，然而，Bootstrap 4使用flexbox来处理布局。Flexbox布局使我们更容易设计出一个灵活的响应式布局结构，而不需要使用float或positioning。因此，我们使用Bootstrap 4代替Bootstrap 3来达到灵活设计的目的。

步骤:

我们为GFG的在线DSA课程和区块链课程创建一个简单的卡片。Bootstrap类d-flex定义了一个flexbox容器。
flexbox容器中的直接HTML元素被称为flex items。
flex-direction指定了flexbox容器中的flex项目的方向。
我们使用flex-row类，在flexbox容器中水平移动flex项目。
justify-content类规定了在flexbox容器中沿flex方向的flex项目的对齐方式。
我们使用justify-content-end将flexbox容器末端的flex项目根据f lex-direction水平或垂直对齐。
我们使用align-items-center，根据flex-direction，在flexbox容器的中心，水平或垂直地对齐flex项目。这将适用于justify-content属性的相反轴。

Bootstrap CDN：我们需要在HTML head元素中添加以下CDN文件。

<link rel=”stylesheet” href=”https://cdn.jsdelivr.net/npm/bootstrap@4.6.1/dist/css/bootstrap.min.css”>
<script src=”https://cdn.jsdelivr.net/npm/jquery@3.5.1/dist/jquery.slim.min.js”></script>
<script src=”https://cdn.jsdelivr.net/npm/bootstrap@4.6.1/dist/js/bootstrap.bundle.min.js”></script>

例子：在这个例子中，我们使用了flexbox，用flex属性将卡片垂直排列在中间，水平排列在右边。

<!DOCTYPE html>
<html>
<head>
    <link rel="stylesheet"
          href=
"https://cdn.jsdelivr.net/npm/bootstrap@4.6.1/dist/css/bootstrap.min.css">
    <script src=
"https://cdn.jsdelivr.net/npm/jquery@3.5.1/dist/jquery.slim.min.js">
    </script>
    <script src=
"https://cdn.jsdelivr.net/npm/bootstrap@4.6.1/dist/js/bootstrap.bundle.min.js">
    </script>
    <style>
        .bg-container {
            background-image: url(
"https://media.geeksforgeeks.org/wp-content/uploads/20211108163509/GeeksforGeeksSchoolAGFGInitiativeForSchoolStudents.png"
            );
            background-size: cover;
            height: 100vh;
        }
 
        .card {
            background-color:#19f7ecea;
            padding: 20px;
            width: 600px;
            height: 200px;
            border-radius: 15px;
            margin-right: 30px;
        }
 
        .main-heading {
            color: rgba(0, 0, 0, 0.849);
            font-family: "Bree Serif";
            font-size: 30px;
        }
 
        .paragraph1 {
            font-family: "Roboto";
            font-size: 15px;
        }
 
        .paragraph2 {
            font-size: 25px;
        }
 
        .button-container {
            text-align: center;
            margin: 10px;
        }
 
        .button {
            border-radius: 10px;
            background-color:#19f7ecea;
            padding: 5px;
            margin-top:40px;
            width: 250px;
            font-size: 20px;
            font-family: "Roboto";
        }
      </style>
</head>
<body>
    <div class="bg-container
                d-flex
                flex-row
                justify-content-end
                align-items-center">
        <div class="card">
            <h1 class="main-heading">
              Data Structure in C++ by Jitendra Kumar
            </h1>
            <p class="paragraph1">
              This course designed for beginners who wants to
              improve their programming skills and get ready
              for placement.</p>
 
 
            <p class="paragraph2">12000/-</p>
 
 
            <div class="button-container">
                <button class="button">Register Now</button>
            </div>
        </div>
        <div class="card">
            <h1 class="main-heading">
              Blockchain Technology
              by Vinod Kumar
            </h1>
            <p class="paragraph1">
              This course designed for college student
              who wants to know about basic knowledge
              of Blockchain.
            </p>
 
 
            <p class="paragraph2">20000/-</p>
 
 
            <div class="button-container">
                <button class="button">
                  Register Now
                </button>
            </div>
        </div>
     </div>
</body>
</html>

输出:

Bootstrap 3是否使用Flexbox？