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CSS

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CSS Base

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Babel includes JSX processing.

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HTML 

              
                <article>
  <nav>
    Jump to...
    <ul>
      <li><a href="#section-1">Section 1</a></li>
      <li><a href="#section2">Section 2</a></li>
      <li><a href="#section-3">Section 3</a></li>
      <li><a href="#section-4">Section 4</a></li>
      <li><a href="#section-5">Section 5</a></li>
    </ul>
  </nav>
  <section id="section-1">
    <h2>Section 1</h2>
    <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. In sint sunt fuga ut, itaque labore est quos saepe porro repudiandae dicta, vero nam ex aliquid aut consequatur adipisci modi! Totam? Eos dolores quos, sequi molestias ex assumenda sint incidunt unde magni culpa, maxime natus! Eum amet harum enim laboriosam consequuntur dicta quibusdam voluptatem, minima voluptas, libero esse veniam vel! Mollitia?</p>
    <p>Minus consequuntur ipsa doloremque delectus accusamus eveniet ipsum, doloribus illum neque harum incidunt? Fuga, provident! Adipisci esse quisquam tempore officia dicta nobis, est odio consequuntur deleniti doloribus quia, quaerat incidunt!</p>
    <p>Tempore, minima impedit iure officiis minus fuga vitae repudiandae a eos quisquam quo, necessitatibus aspernatur! Inventore, sit ex dolorem tenetur officia quasi rem qui, debitis similique earum provident ipsam omnis. Cupiditate iure officia cumque minima a itaque dicta, temporibus autem necessitatibus! Voluptatem dignissimos cepturi, adipisci neque eaque quisquam odit laudantium asperiores iste, eius atque totam distinctio enim magnam pariatur non!</p>
  </section>

  <section id="section-2">
    <h2>Section 2</h2>
    <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. In sint sunt fuga ut, itaque labore est quos saepe porro repudiandae dicta, vero nam ex aliquid aut consequatur adipisci modi! Totam? Eos dolores quos, sequi molestias ex assumenda sint incidunt unde magni culpa, maxime natus! Eum amet harum enim laboriosam consequuntur dicta quibusdam voluptatem, minima voluptas, libero esse veniam vel! Mollitia?</p>
    <p>Minus consequuntur ipsa doloremque delectus accusamus eveniet ipsum, doloribus illum neque harum incidunt? Fuga, provident! Adipisci esse quisquam tempore officia dicta nobis, est odio consequuntur deleniti doloribus quia, quaerat incidunt!</p>
    <p>Tempore, minima impedit iure officiis minus fuga vitae repudiandae a eos quisquam quo, necessitatibus aspernatur! Inventore, sit ex dolorem tenetur officia quasi rem qui, debitis similique earum provident ipsam omnis. Cupiditate iure officia cumque minima a itaque dicta, temporibus autem necessitatibus! Voluptatem dignissimos cepturi, adipisci neque eaque quisquam odit laudantium asperiores iste, eius atque totam distinctio enim magnam pariatur non!</p>
  </section>

  <section id="section-3">
    <h2>Section 3</h2>
    <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. In sint sunt fuga ut, itaque labore est quos saepe porro repudiandae dicta, vero nam ex aliquid aut consequatur adipisci modi! Totam? Eos dolores quos, sequi molestias ex assumenda sint incidunt unde magni culpa, maxime natus! Eum amet harum enim laboriosam consequuntur dicta quibusdam voluptatem, minima voluptas, libero esse veniam vel! Mollitia?</p>
    <p>Minus consequuntur ipsa doloremque delectus accusamus eveniet ipsum, doloribus illum neque harum incidunt? Fuga, provident! Adipisci esse quisquam tempore officia dicta nobis, est odio consequuntur deleniti doloribus quia, quaerat incidunt!</p>
    <p>Tempore, minima impedit iure officiis minus fuga vitae repudiandae a eos quisquam quo, necessitatibus aspernatur! Inventore, sit ex dolorem tenetur officia quasi rem qui, debitis similique earum provident ipsam omnis. Cupiditate iure officia cumque minima a itaque dicta, temporibus autem necessitatibus! Voluptatem dignissimos cepturi, adipisci neque eaque quisquam odit laudantium asperiores iste, eius atque totam distinctio enim magnam pariatur non!</p>
  </section>

  <section id="section-4">
    <h2>Section 4</h2>
    <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. In sint sunt fuga ut, itaque labore est quos saepe porro repudiandae dicta, vero nam ex aliquid aut consequatur adipisci modi! Totam? Eos dolores quos, sequi molestias ex assumenda sint incidunt unde magni culpa, maxime natus! Eum amet harum enim laboriosam consequuntur dicta quibusdam voluptatem, minima voluptas, libero esse veniam vel! Mollitia?</p>
    <p>Minus consequuntur ipsa doloremque delectus accusamus eveniet ipsum, doloribus illum neque harum incidunt? Fuga, provident! Adipisci esse quisquam tempore officia dicta nobis, est odio consequuntur deleniti doloribus quia, quaerat incidunt!</p>
    <p>Tempore, minima impedit iure officiis minus fuga vitae repudiandae a eos quisquam quo, necessitatibus aspernatur! Inventore, sit ex dolorem tenetur officia quasi rem qui, debitis similique earum provident ipsam omnis. Cupiditate iure officia cumque minima a itaque dicta, temporibus autem necessitatibus! Voluptatem dignissimos cepturi, adipisci neque eaque quisquam odit laudantium asperiores iste, eius atque totam distinctio enim magnam pariatur non!</p>
  </section>

  <section id="section-5">
    <h2>Section 5</h2>
    <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. In sint sunt fuga ut, itaque labore est quos saepe porro repudiandae dicta, vero nam ex aliquid aut consequatur adipisci modi! Totam? Eos dolores quos, sequi molestias ex assumenda sint incidunt unde magni culpa, maxime natus! Eum amet harum enim laboriosam consequuntur dicta quibusdam voluptatem, minima voluptas, libero esse veniam vel! Mollitia?</p>
    <p>Minus consequuntur ipsa doloremque delectus accusamus eveniet ipsum, doloribus illum neque harum incidunt? Fuga, provident! Adipisci esse quisquam tempore officia dicta nobis, est odio consequuntur deleniti doloribus quia, quaerat incidunt!</p>
    <p>Tempore, minima impedit iure officiis minus fuga vitae repudiandae a eos quisquam quo, necessitatibus aspernatur! Inventore, sit ex dolorem tenetur officia quasi rem qui, debitis similique earum provident ipsam omnis. Cupiditate iure officia cumque minima a itaque dicta, temporibus autem necessitatibus! Voluptatem dignissimos cepturi, adipisci neque eaque quisquam odit laudantium asperiores iste, eius atque totam distinctio enim magnam pariatur non!</p>
  </section>
</article>
!

CSS 

              
                body {
  font-size: 125%;
  line-height: 1.5;
}

nav,
nav ul {
  display: flex;
  flex-flow: row wrap;
}

nav {
  background: #2b2f2c;
  color: #fff;
  padding: 1rem;
  position: sticky;
  top: 0;
}

nav ul {
  list-style: none;
  margin: 0;
}

nav li {
  margin-right: 25px;
}

nav li a {
  color: yellow;
}

section {
  padding: 1rem 3rem;
}

section:target {
  background: lightyellow;
}
!

JS
!
999px

Console