JS Disco

<body>
  <h1 style="margin: auto;width: -moz-fit-content;margin-top: 34vh;font-size: 6em;">YEAH!<br>
  LET'S PARTAYYYY</h1>
  <script>
    const r = n => Math.round(Math.random() * n);
    const rrgb = rrgb => `rgb(${r(256)}, ${r(256)}, ${r(256)})`;
    function disco() {
      document.body.setAttribute('style', `color: ${rrgb()} !important; background-color: ${rrgb()} !important`);
    }
    window.setInterval(1750, disco);
  </script>
</body>