e different variants of the experiment by using `body[amp-x-name-of-experiment="nameOfVariant"`].
  -->
  <style amp-custom>
    body[amp-x-button-color-experiment="0"] .button-color-experiment {
      background-color: yellow;
      color: black;
    }
    body[amp-x-button-color-experiment="1"] .button-color-experiment {
      background-color: red;
    }
    body[amp-x-button-color-experiment="2"] .button-color-experiment {
      background-color: blue;
    }
  </style>
</head>
<body>

  <!-- ## Basic us