<header class="hero">
  <div class="container">
    <h1>CSS Position</h1>
    <ul class="navbar">
      <li><a href="#">static</a></li>
      <li><a href="#">relative</a></li>
      <li><a href="#">absolute</a></li>
      <li><a href="#">fixed</a></li>
      <li><a href="#" class="current-link">sticky</a></li>
    </ul>
  </div>
</header>
<main class="main container">
  <section class="section position-sticky">
    <h2><code>position: sticky;</code></h2>
    <div class="sticky">This element has <code>position: sticky;</code></div>

    <p class="separator">the above example, the header and the text with blue background and class <code>fixed</code> has<br /><code>position: sticky;</code> <br /></p>

    <p>The header's parent is the document, while the fixed div's parent is the main (with skyblue background)</p>

    <strong><em>
        <p>The text acts as a relative positioned element until it's away 5px away from top. As the main element is scrolled, it acts as a fixed element</p>
      </em></strong>
    <strong><em>
        <p>Similarly, the header text acts as a relative positioned element until it's away 0px away from top. As the page is scrolled it acts as a fixed element</p>
      </em></strong>
    <p>
      <strong style="color: black; display: inline-block; margin-top: 0.1rem; padding: 0.5rem 1rem; background-color:yellowgreen;">
        <code>
          header.hero {
          position: sticky;
          top: 5px;
          }
          <br />
          <br />
          main.main {
          position: relative;
          }
          <br />
          <br />
          div.sticky {
          position: sticky;
          top: 5px;
          }

        </code>
      </strong>
    </p>

  </section>
</main>

* {
  box-sizing: border-box;
  padding: 0;
  margin: 0;
}

body {
  font-family: Arial, Helvetica, sans-serif;
  height: 250vh;
}

.container {
  margin: auto;
  max-width: 900px;
  padding: 1rem;
}

a,
a:visited {
  text-decoration: none;
}

a.current-link {
  background-color: navy;
}

header.hero {
  background-color: royalblue;
  position: sticky;
  top: 0;
  box-shadow: 0px 0px 10px #000;
  font-size: 1.2rem;
  font-family: "Franklin Gothic Medium", "Arial Narrow", Arial, sans-serif;
  text-transform: uppercase;
}

.hero .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.hero h1 {
  font-size: 1.2rem;
  letter-spacing: 0.3rem;
  padding: 0.5rem;
}

.hero ul {
  list-style: none;
}

.hero ul li {
  display: inline-block;
  margin-right: 1rem;
}

.hero ul li a {
  color: #fff;
  padding: 0.5rem 0.75rem;
  border-radius: 0.5rem;
}

.main {
  height: 100vh;
  position: relative;
}

.separator {
  text-align: center;
  margin: 1rem 0;
  font-size: 1.1rem;
}

.section {
  padding: 1rem;
  margin: 2rem auto;
  max-width: 400px;
  background-color: lightskyblue;
  /* text-align: center; */
  color: white;
  max-width: 100%;
  height: 100%;
}

.section h2 {
  font-size: 1.3rem;
  background-color: darkgreen;
  padding: 1rem;
}

.section p {
  font-size: 1.1rem;
  background-color: darkgreen;
  padding: 1rem;
}

.section .sticky {
  background: navy;
  padding: 1rem;
  position: sticky;
  top: 5px;
  font-size: 1.3rem;
}

@media screen and (max-width: 800px) {
  .hero .container {
    flex-direction: column;
    justify-content: center;
  }

  .hero h1 {
    margin-bottom: 1rem;
  }
}

@media screen and (max-width: 600px) {
  .hero h1 {
    margin-bottom: 0;
  }

  .hero ul {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
  }
  .hero ul li {
    padding: 0.25 0;
    margin: 1.5rem 0 0 0;
    font-size: 1rem;
  }
}