<a href="#modal-1" class="link">Open Modal</a>

<div data-am-modal id="modal-1">
  <a href="#!" class="modal-overlay"></a>
  <div class="modal-dialog">
    <div class="modal-content">
      <a href="#!" class="modal-close">Close</a>
      <h1>CSS Modal</h1>
      <p>Cras mattis consectetur purus sit amet fermentum. Cras justo odio, dapibus ac facilisis in, egestas eget quam. Morbi leo risus, porta ac consectetur ac, vestibulum at eros.</p> <p>Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Vivamus sagittis lacus vel augue laoreet rutrum faucibus dolor auctor.</p> <p>Aenean lacinia bibendum nulla sed consectetur. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Donec sed odio dui. Donec ullamcorper nulla non metus auctor fringilla.</p> <p>Cras mattis consectetur purus sit amet fermentum. Cras justo odio, dapibus ac facilisis in, egestas eget quam. Morbi leo risus, porta ac consectetur ac, vestibulum at eros.</p> <p>Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Vivamus sagittis lacus vel augue laoreet rutrum faucibus dolor auctor.</p> <p>Aenean lacinia bibendum nulla sed consectetur. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Donec sed odio dui. Donec ullamcorper nulla non metus auctor fringilla.</p> <p>Cras mattis consectetur purus sit amet fermentum. Cras justo odio, dapibus ac facilisis in, egestas eget quam. Morbi leo risus, porta ac consectetur ac, vestibulum at eros.</p> <p>Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Vivamus sagittis lacus vel augue laoreet rutrum faucibus dolor auctor.</p> <p>Aenean lacinia bibendum nulla sed consectetur. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Donec sed odio dui. Donec ullamcorper nulla non metus auctor fringilla.</p>
    </div>
  </div>
</div>

[data-am-modal] {
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  overflow-x: hidden;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  z-index: 999;
  
  // Open/close
  width: 0;
  height: 0;
  opacity: 0;
  &:target {
    width: auto;
    height: auto;
    opacity: 1;
    transition: opacity 400ms ease;
    .modal-overlay {
      position: fixed;
      top: 0;
      bottom: 0;
      left: 0;
      right: 0;
      cursor: default;
      background-color: rgba(0,0,0,0.4);
      z-index: 1;
    }
  }
  
  .modal-dialog {
    position: relative;
    width: calc(100% - 30px);
    max-width: 600px;
    margin: 15px auto;
    z-index: 2;
  }

  .modal-content {
    background-color: white;
    padding: 30px;
  }

  .modal-close {
    position: absolute;
    top: 15px;
    right: 15px;
  }
}

/* Base Styling */

body {
  margin: 0;
  font-family: 'Open Sans', sans-serif;
}

.link {
  display: inline-block;
  padding: 15px;
  background-color: #1e91c7;
  color: #fff;
  border-radius: 5px;
  text-decoration: none;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}