node_modules/material-design-lite/src/animation/demo.html

    <div class="demo-preview-block demo-animation demo-js-animation">
      <div class="demo-animation__container">
        <div class="demo-animation__container-background">Click me to animate</div>
        <div class="demo-animation__container-foreground"></div>
        <div class="demo-animation__movable demo-animation--position-0 mdl-shadow--2dp"></div>
      </div>
    </div>