html - Bootstrap 列在小屏幕尺寸下没有响应(移动)

Question

我有一个正在使用 Bootstrap 构建的页面。 “服务”部分以 lg 和 md 尺寸正确显示，但不能以 sm 或 xs(移动)尺寸显示。我在这里错过了什么。我试过包括 col-sm-12 和 col-xs-12，但是当我将屏幕尺寸缩小到移动设备时，它确实有响应。任何帮助表示赞赏。如果您想查看网站，请点击此处链接:http://pctechtips.org/apps/itcomp/

<div class="py-4 bg-light" id="prices">
    <div class="container">
      <div class="row">
        <div class="col-md-12">
          <h1 class="text-center">Service Prices</h1>
        </div>
      </div>
      <div class="row">
        <div class="col-md-12">
          <p class="lead text-center">Bellow you can see a brief description of our services and price. These fall into three main category: Desktop Support, System Maintanance, and Network Installation. If you would like to know more details, go to the Service page.</p>
        </div>
      </div>
      <div class="row">
        <div class="col-md-4 p-3">
          <div class="card box-shadow rounded border border-secondary" >
            <img class="card-img-top" src="assets/styleguide/thinkstockphotos-479282847.jpg">
            <div class="card-body">
              <h3 class="text-center">Desktop Support</h3>
              <p class="card-text">We provide online or in person Desktop Support by helping user solve technical issues. We fix computers, laptops: adding memory (RAM), replacing hard drive, data migration, virus removal, slow computer.</p>
              <div class="d-flex justify-content-between align-items-center">
                <a class="btn btn-primary" href="services.html#services">learn more</a>
                <h5 contenteditable="true">60 $ 1hr</h5>
              </div>
            </div>
          </div>
        </div>
        <div class="col-md-4 p-3">
          <div class="card box-shadow border border-secondary rounded">
            <img class="card-img-top" src="assets/styleguide/photo-1506399309177-3b43e99fead2.jpg">
            <div class="card-body">
              <h3 class="text-center">System Administration</h3>
              <p class="card-text">We provide Windows Server and Linux Server administration. This includes checking logs. Schedule regular backups. User administration to make sure user have access to network resources.</p>
              <div class="d-flex justify-content-between align-items-center">
                <a class="btn btn-primary" href="services.html#services">learn more</a>
                <h5 style="">100 $ 1hr</h5>
              </div>
            </div>
          </div>
        </div>
        <div class="col-md-4 p-3">
          <div class="card box-shadow border border-secondary rounded">
            <img class="card-img-top" src="assets/styleguide/photo-1544197150-b99a580bb7a8.jpg">
            <div class="card-body">
              <h3 class="text-center">Network Installation</h3>
              <p class="card-text">Whether is a small or large project we will be able to assist you. We can assist with installation of network devices like router, switches, firewall, modems, wireless access points, network printers, servers.</p>
              <div class="d-flex justify-content-between align-items-center">
                <a class="btn btn-primary" href="services.html#services">learn more</a>
                <h5>150 $ 1hr</h5>
              </div>
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>

Answer 1

在你的头标签中包含元标签

<meta name="viewport" content="width=device-width, initial-scale=1.0">