index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <link
      rel="stylesheet"
      href="https://unpkg.com/@picocss/pico@latest/css/pico.classless.min.css"
    />
    <title>Hello, world!</title>
  </head>
  <body>
    <header>
      <!-- Header content -->
      <hgroup>
        <h1>Hello, world!</h1>
        <h2>
          This website uses
          <a href="https://picocss.com/examples/classless/" target="_blank">
            Pico.css classless
          </a>
          , a CSS framework that uses only HTML tags for styling.
        </h2>
      </hgroup>
      <a href="https://picocss.com/docs/" target="_blank">
        <button>Click here for more information about Pico.css</button>
      </a>
    </header>
    <main>
      <!-- Main content -->
    </main>
    <footer>
      <!-- Footer content -->
    </footer>
  </body>
</html>