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HTML

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Insecure Resource

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CSS

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CSS Base

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JavaScript

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Babel includes JSX processing.

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HTML 

              
                <div>
  <p>
    <span class="label">Challenge ::</span> 
    Recreate Android/Jellybean link loading animation with pure CSS.
  </p>
  <p>
    <span class="label">Reference/Example ::</span>
    <a class="open-profile" href="https://codepen.io/dragontheory/pen/JjorrKL">
      https://codepen.io/dragontheory/pen/JjorrKL
    </a>
  </p>
  <p>
    <span class="label">Description ::</span> 
    Three stagarred animated "holes" or knockouts in link underline.
  </p>
  <p>
    <span class="label">Requirements ::</span>
    <ul>
      <li>Three stagarred animations on one HTML element (anchor tag)</li>
      <li>Each animated element is 6px width 1px height</li>
      <li>No extra markup (just the anchor tag)</li>
      <li>Must work with multiple lines (wrapping text)</li>
      <li>Pure CSS (no JS)</li>
      <li>Future proofed - Does not otherwise affect or limit anchor tag or link text string from other/future manipulation</li>
      <li>No absolute or static positioning</li>
      <li>"Hole" matches anchor element background color</li>
      <li>Cross/backward broswer compatible with FF, Chrome, Sufari, Edge, (IE11?)</li>
      <li>Responsive</li>
      <li>Performant</li>
    </ul>
  </p>
  <p>
    <span class="label">Single line test :: </span>
    <a href="#" class="open-profile">This is a link on a single line</a>.
  </p> 
  <div style="width: 300px;">
    <p>
      <span class="label">Multi line test :: </span>
      <a href="#" class="open-profile">This is a link that wrapps to a second line</a>.</p>
  </div>
<p>
  <span class="label">Links ::</span>
  <a href="https://css-tricks.com/css-techniques-and-effects-for-knockout-text/">https://css-tricks.com/css-techniques-and-effects-for-knockout-text</a>
</p>
</div>
!

CSS 

              
                html,
body {
  background-color: #1d1e22;
  font-family: Calibri;
  color: #fff;
}

.label {color: #999;}

a {
  color: #2e9cd3;
  background: 
    /* knock-out */
    linear-gradient(#FFFFFF, #FFFFFF) left bottom / 6px 1px no-repeat;
    /* solid line 
    linear-gradient(currentColor, currentColor) left bottom / 100% 1px no-repeat;*/
  -webkit-animation: break01 2s infinite, break02 2s 0.5s infinite, break03 2s 1s infinite;
          animation: break01 2s infinite, break02 2s 0.5s infinite, break03 2s 1s infinite;
  -webkit-transition: background 250ms ease;
          transition: background 250ms ease;
}
@-webkit-keyframes break01 {
  from {background-position: left bottom;}
  to {background-position: right bottom;}
}
@keyframes break01 {
  from {background-position: left bottom;}
  to {background-position: right bottom;}
}
@-webkit-keyframes break02 {
  from {background-position: left bottom;}
  to {background-position: right bottom;}
}
@keyframes break02 {
  from {background-position: left bottom;}
  to {background-position: right bottom;}
}
@-webkit-keyframes break03 {
  from {background-position: left bottom;}
  to {background-position: right bottom;}
}
@keyframes break03 {
  from {background-position: left bottom;}
  to {background-position: right bottom;}
}
!

JS 

              
                // no JS
!
999px

Console