rxjs/memory-game/index.html

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    <title>Document</title>
    <style>
      .parent {
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        width: 50%;
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        display: table-cell;
        border: 1px solid rgba(0, 0, 0, 0.5);
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      .parent.perspective .child {
        transform: rotateX(40deg);
        transition: all 0.3s ease-in;
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  <body>
    <div id="info">Train Your Memory!</div>
    <div id="grid" class="grid parent perspective">
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      </div>
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    <script src="index.ts"></script>
  </body>
</html>