Lock an Element to the Browser Window with Fixed Positioning

Summary

The fixed position property locks an element relative to the browser window.
Removes the element from the normal flow of the document.
Elements with a fixed position won’t move when the user scrolls.

Final Code

<style>
  body {
    min-height: 150vh;
  }
  #navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: #767676;
  }
  nav ul {
    margin: 0px;
    padding: 5px 0px 5px 30px;
  }
  nav li {
    display: inline;
    margin-right: 20px;
  }
  a {
    text-decoration: none;
  }
</style>
<body>
  <header>
    <h1>Welcome!</h1>
    <nav id="navbar">
      <ul>
        <li><a href="">Home</a></li>
        <li><a href="">Contact</a></li>
      </ul>
    </nav>
  </header>
  <p>I shift up when the #navbar is fixed to the browser window.</p>
</body>