响应图像不会跟随col 12

Question

在小屏幕中，我的响应图像会变小，直到消失，即使是我指定的图像在小屏幕上互相覆盖，因此我的col-md-6 col-sm-12。知道我的密码怎么了吗？

​

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>

<div class="row">
  <div class="col-md-12 d-flex">
    <div class="media block-6 services d-flex align-items-center">
      <div class="col-md-6 col-sm-12 d-flex">
        <div class="media-body pl-4 pl-md-0 pr-md-4 text-md-left">
          <h3 class="heading">Title</h3>
          <p class="mb-0">Description</p>
        </div>
      </div>
      <div class="col-md-6 col-sm-12 d-flex">
        <div class="d-flex align-items-center justify-content-center">
          <img class="img-fluid" src="https://www.plantes-et-sante.fr/images/photo-8.jpg_720_1000_2">
        </div>
      </div>
    </div>
  </div>
</div>

​

继续在这里调整屏幕的大小，因为我知道我需要弹性显示器。

https://jsfiddle.net/ero14xqf/

Answer 1

.col-*必须始终包含在.row.

<div class="row">
  <div class="col-md-12 d-flex">
    <div class="row media block-6 services d-flex align-items-center">
      <div class="col-md-6 col-sm-12 d-flex">
        <div class="media-body pl-4 pl-md-0 pr-md-4 text-md-left">
          <h3 class="heading">Title</h3>
          <p class="mb-0">Description</p>
        </div>
      </div>
      <div class="col-md-6 col-sm-12 d-flex">
        <div class="d-flex align-items-center justify-content-center">
          <img class="img-fluid" src="https://www.plantes-et-sante.fr/images/photo-8.jpg_720_1000_2">
        </div>
      </div>
    </div>
  </div>
</div>