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CSS

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HTML 

              
                <!-- Visit https://nicolaskadis.info/posts/pure-css-flip-cards-using-bootstrap-4-and-css-grid-no-js for an explanation -->
<div class="container">
  <div class="row">
          <!-- Card 1 -->
    <div class="col-md-4 card-container">
      <div class="card-flip">
        <!-- Card 1 Front -->
        <div class="card front">
          <span class="fa fa-4x fa-smile-o text-center"></span>
          <div class="card-block">
            <h4 class="card-title text-center">Front Card Title</h4>
            <h6 class="card-subtitle mb-2 text-muted text-center">Front Card subtitle</h6>
            <p class="card-text">Some quick example text to build on the card title and make up the bulk of the card's content.</p>
          </div>
        </div>
        <!-- End Card 1 Front -->

        <!-- Card 1 Back -->
        <div class="card back">
          <div class="card-block">
            <h4 class="card-title">Back Card Title</h4>
            <h6 class="card-subtitle mb-2 text-muted">Back Card subtitle</h6>
            <p class="card-text">Some quick example text to build on the card title and make up the bulk of the card's content.</p>
            <a href="#" class="card-link">Card link</a>
            <a href="#" class="card-link">Another link</a>
          </div>
        </div>
        <!-- End Card 1 Back -->
      </div>
    </div>
    <!-- End Card 1 -->

    <!-- Card 2 -->
    <div class="col-md-4 card-container">
      <div class="card-flip">
        <!-- Card 2 Front -->
        <div class="card front">
          <img src="https://nikonrumors.com/wp-content/uploads/2014/03/Nikon-1-V3-sample-photo.jpg" class="card-img-top img-fluid">
          <div class="card-block">
            <h4 class="card-title">Front Card Title</h4>
            <p class="card-text">Some quick example text to build on the card title and make up the bulk of the card's content.</p>
            <p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>
          </div>
        </div>
        <!-- End Card 2 Front -->

        <!-- Card 2 Back -->
        <div class="card back">
          <div class="card-header">
            Featured
          </div>
          <div class="card-block">
            <h4 class="card-title">Special title treatment</h4>
            <p class="card-text">With supporting text below as a natural lead-in to additional content.</p>
            <a href="#" class="btn btn-primary">Go somewhere</a>
          </div>
        </div>
        <!-- End Card 2 Back -->
      </div>
    </div>
    <!-- End Card 2 -->

    <!-- Card 3 -->
    <div class="col-md-4 card-container">
      <div class="card-flip">
        <!-- Card 3 Front -->
        <div class="card front">
          <img src="http://www.usa-essays.com/blog/wp-content/uploads/2017/09/sample-5-1024x768.jpg" class="card-img-top img-fluid">
          <div class="card-block">
            <h4 class="card-title">Front Card Title</h4>
            <p class="card-text">Some quick example text to build on the card title and make up the bulk of the card's content.</p>
          </div>
          <ul class="list-group list-group-flush">
            <li class="list-group-item">Cras justo odio</li>
            <li class="list-group-item">Dapibus ac facilisis in</li>
            <li class="list-group-item">Vestibulum at eros</li>
          </ul>
          <div class="card-block">
            <p class="card-text">Some more text</p>
          </div>
        </div>
        <!-- End Card 3 Front -->

        <!-- Card 3 Back -->
        <div class="card back text-center">
          <div class="card-header">
            Featured
          </div>
          <div class="card-block">
            <h4 class="card-title">Special title treatment</h4>
            <p class="card-text">With supporting text below as a natural lead-in to additional content.</p>
            <a href="#" class="btn btn-primary">Go somewhere</a>
          </div>
          <div class="card-footer text-muted">
            2 days ago
          </div>
        </div>
        <!-- End Card 3 Back -->
      </div>
    </div>
    <!-- End Card 3 -->

    <!-- Card 4 -->
    <div class="col-md-4 card-container">
      <div class="card-flip">
        <!-- Card 4 Front -->
        <div class="card front text-right">
          <div class="card-block">
            <span class="fa fa-4x fa-smile-o"></span>
            <h4 class="card-title">Front Title aligned to the right</h4>
            <h6 class="card-subtitle text-muted">Front Sub-title</h6>
            <p class="card-text">Front Text aligned to the right</p>
          </div>
        </div>
        <!-- End Card 4 Front -->

        <!-- Card 4 Back -->
        <div class="card back text-center">
          <div class="card-block">
            <h4 class="card-title">Back Title aligned to the center</h4>
            <p class="card-text">With supporting text below as a natural lead-in to additional content.</p>
            <a href="#" class="btn btn-primary">Go somewhere</a>
          </div>
        </div>
        <!-- End Card 4 Back -->
      </div>
    </div>
    <!-- End Card 4 -->

    <!-- Card 5 -->
    <div class="col-md-4 card-container">
      <div class="card-flip">
        <!-- Card 5 Front -->
        <div class="card front card-inverse">
          <img class="card-img img-fluid" src="http://imgsv.imaging.nikon.com/lineup/lens/zoom/normalzoom/af-s_dx_18-300mmf_35-56g_ed_vr/img/sample/sample4_l.jpg" alt="Card image">
          <div class="card-img-overlay">
            <h4 class="card-title">Card title</h4>
            <p class="card-text">This is a wider card with supporting text below as a natural lead-in to additional content. This content is a little bit longer.</p>
            <p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>
          </div>
        </div>
        <!-- End Card 5 Front -->

        <!-- Card 5 Back -->
        <div class="card back">
          <div class="card-header">
            <ul class="nav nav-tabs card-header-tabs">
              <li class="nav-item">
                <a class="nav-link active" href="#">Active</a>
              </li>
              <li class="nav-item">
                <a class="nav-link" href="#">Link</a>
              </li>
              <li class="nav-item">
                <a class="nav-link disabled" href="#">Disabled</a>
              </li>
            </ul>
          </div>
          <div class="card-block">
            <h4 class="card-title">Special title treatment</h4>
            <p class="card-text">With supporting text below as a natural lead-in to additional content.</p>
            <a href="#" class="btn btn-primary">Go somewhere</a>
          </div>
        </div>
        <!-- End Card 5 Back -->
      </div>
    </div>
    <!-- End Card 5 -->

    <!-- Card 6 -->
    <div class="col-md-4 card-container">
      <div class="card-flip">
        <!-- Card 6 Front -->
        <div class="card front">
          <ul class="list-group list-group-flush">
            <li class="list-group-item">Cras justo odio</li>
            <li class="list-group-item">Dapibus ac facilisis in</li>
            <li class="list-group-item">Vestibulum at eros</li>
          </ul>
        </div>
        <!-- End Card 6 Front -->

        <!-- Card 6 Back -->
        <div class="card back">
          <div class="card-block">
            <p>Some example short text</p>
            <a href="#" class="btn btn-outline-primary">Read More</a>
          </div>
        </div>
        <!-- End Card 6 Back -->
      </div>
    </div>
    <!-- End Card 6 -->
  </div>
</div>
!

CSS 

              
                /* Visit https://nicolaskadis.info/posts/pure-css-flip-cards-using-bootstrap-4-and-css-grid-no-js for an explanation */

/* for demo purposes */
.card {
  margin: 10px 10px;
}

/* Flip Cards CSS */
.card-container {
  display: grid;
  perspective: 700px;
}

.card-flip {
  display: grid;
  grid-template: 1fr / 1fr;
  grid-template-areas: "frontAndBack";
  transform-style: preserve-3d;
  transition: all 0.7s ease;
}

.card-flip div {
  backface-visibility: hidden;
  transform-style: preserve-3d;
}

.front {
  grid-area: frontAndBack;
}

.back {
  grid-area: frontAndBack;
  transform: rotateY(-180deg);
}

.card-container:hover .card-flip {
  transform: rotateY(180deg);
}
!

JS 

              
                /* NO JAVASCRIPT */

/* Visit https://nicolaskadis.info/posts/pure-css-flip-cards-using-bootstrap-4-and-css-grid-no-js for an explanation */
!
999px

Console