Technical Documentation Page - Build a Technical Documentation Page

It keeps on saying that each .main-section should have an id that matches the text of its first child, having any spaces in the child’s text replaced with underscores (_ ) for the id’s. But I did that, pliz help

  **Your code so far**
/* file: index.html */
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8"/>
  <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
  <title>Technical Documentation Page</title>
  <link rel="stylesheet" href="styles.css"/>
  </head>
  <body>
    <main id="main-doc">
      <section class="main-section" id="introduction">
        <header>Introduction</header>
        </section>
      <section class="main-section" id="what-you-should-already-know">
        <header>What you should already know</header>
        <p></p>
        <p></p>
        <p></p>
<code></code>
        <code></code>
        <ol>
          <li></li>
          <li></li>
        </ol>
        </section>
      <section class="main-section" id="javScript-and-java">
        <header>JavScript and Java</header>
        <p></p>
        <p></p>
        <p></p>
<code></code>
        <ul>
          <li></li>
        </ul>
</section>
      <section class="main-section" id="hello-world">
        <header>Hello World</header>
        <p></p>
        <p></p>
<code></code>
        <ul>
          <li></li>
        </ul>
      </section>
      <section class="main-section" id="variables">
        <header>Variables</header>
        <p></p>
        <p></p>
<code></code>
        <ul>
          <li></li>
        </ul>
      </section>
      </main>
    </body>
    </html>
/* file: styles.css */

  **Your browser information:**

User Agent is: Mozilla/5.0 (Windows NT 6.3; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/105.0.0.0 Safari/537.36

Challenge: Technical Documentation Page - Build a Technical Documentation Page

Link to the challenge:

I see you did not match the capitalization?

Thanks so much. it worked