Learn CSS Flexbox by Building a Photo Gallery - Step 5

Hello
My bad, this is very basic but I don’t know what went wrong. Can you please correct me?

<!-- file: index.html -->

<!-- User Editable Region -->

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Photo Gallery</title>
    <link rel="stylesheet" href="./styles.css">
  </head>
  <body>
    <header class="header">
      <div class="gallery">
        <img><img><img><img><img><img><img><img><img>
      </div>
      
      <h1>css flexbox photo gallery</h1>
      
    </header>
  </body>
</html>

<!-- User Editable Region -->

/* file: styles.css */

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36 Edg/120.0.0.0

Challenge Information:

Learn CSS Flexbox by Building a Photo Gallery - Step 5

Sorry, I figured it out.