CSS transition

Part of the JavaScript in Action section of Coddy's HTML journey — lesson 23 of 27.

Challenge

Easy

Add a smooth animation for the side navigation when it opens and closes:

In the CSS for the side navigation, add the transition property.
Set it so that changes to the width property happen smoothly over 0.3–0.5 seconds.

This will make the navigation slide in and out smoothly when the buttons are clicked.

Try it yourself

<!DOCTYPE html>
<html>
<head>
  <title>Space Exploration</title>
  <link rel="stylesheet" href="style.css">
</head>
<body>
  <div id="sideNav" class="sidenav">
    <button id="closeBtn" class="close-btn">&times;</button>
    <a href="#apollo">Apollo Missions</a>
    <a href="#iss">International Space Station</a>
    <a href="#mars">Mars Rovers</a>
    <a href="#jameswebb">James Webb Telescope</a>
  </div>

  <header>
    <button id="openBtn" class="open-btn">&#9776; Menu</button>
    <h1>Space Exploration</h1>
  </header>

  <main>
    <section id="apollo">
      <h2>Apollo Missions</h2>
      <p>
        The Apollo program, carried out by NASA in the 1960s and 1970s, 
        successfully landed humans on the Moon for the first time in 1969.
      </p>
    </section>

    <section id="iss">
      <h2>International Space Station</h2>
      <p>
        The ISS is a multinational research laboratory in low Earth orbit, 
        continuously inhabited since 2000 by astronauts and scientists.
      </p>
    </section>

    <section id="mars">
      <h2>Mars Rovers</h2>
      <p>
        Rovers like Spirit, Opportunity, Curiosity, and Perseverance 
        have been exploring the Martian surface, searching for signs of past life.
      </p>
    </section>

    <section id="jameswebb">
      <h2>James Webb Space Telescope</h2>
      <p>
        Launched in 2021, the James Webb Telescope is providing 
        breathtaking images of the universe and studying distant galaxies.
      </p>
    </section>
  </main>

  <script src="script.js"></script>
</body>
</html>