Personal Portfolio Webpage - Build a Personal Portfolio Webpage

Your code so far
they said your navbar should be at top of the view port. sure it is there. but code is not working.

<!-- file: index.html -->
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="styles.css">
    <title>personal portfolio project</title>
  </head>
  <body>
    <header id="header">
    <nav id="navbar">
      <ul><li><a href="#welcome-section" class="nav-link">About</a></li>
      <li><a href="#projects" class="nav-link">Work</a></li>
      <li><a href="#Contacts" class="nav-link">Contacts</a></li></ul>
    </nav></header>
    
      <div id="welcome-section">
      <h1>Hey I am Mimic</h1>
      <h3>a web developer</h3>
    </div>
    <div id="projects">
      <h3><u>These are some of my projects</u></h3>
      <div class="project-tile" >
        <img src="https://cdn.freecodecamp.org/testable-projects-fcc/images/tribute.jpg">
        <p><a href="https://codepen.io/freeCodeCamp/full/zNqgVx">Tribute page</a></p>
</div>
      <div class="project-tile">
        <img src="https://cdn.freecodecamp.org/testable-projects-fcc/images/random-quote-machine.png">
        <p><a href="https://codepen.io/freeCodeCamp/full/qRZeGZ">Random quoto machine</a></p></nav>
    </div>
    <div id="Contacts">
<h1>Let's work together...</h1>
<h6>How do you take your coffee?</h6>
<img src="#GITHUB">
<a href="https://github.com/freecodecamp" id="profile-link" target="_blank">GIT HUB</a>
    </div>
  </body>
  </html>
/* file: styles.css */
@media screen and (min-width: 480px){
  body{
    color: black;
    padding-top: 0px;
    margin-top: 0px;
  }
}
#navbar{
  
  color: white;
  padding-top: 0px;
  margin-top: 0px;
}
#welcome-section{
  background-color: black;
  color:white;
  text-align: center;
}
#projects{
  background-color: Darkblue;
  color: white;
  text-align: center;
  
}
#nav{
  height: 100vh;
}
header{
  position: fixed;
  width: 100%;
  top: 0;
  left: 0;
  background-color: #cc0000;
  color: white;
  font-family: 'Exo 2', sans-serif;
  padding: 1em;
}

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:106.0) Gecko/20100101 Firefox/106.0

Challenge: Personal Portfolio Webpage - Build a Personal Portfolio Webpage

Link to the challenge:

The question asks you to fix the navbar at the top of the screen.
And if you remember there is a position value that will help you do this.
https://www.w3schools.com/css/css_positioning.asp