All of the section elements should be between the opening and closing tags of the main element.

HTML-CSS
1 
 <section>
       <section>
        <h2>Cat Lists</h2>
        <h3>Things cats love:</h3>
        <ul>
          <li>cat nip</li>
          <li>laser pointers</li>
          <li>lasagna</li>
        </ul>
        <figure>
          <img src="https://cdn.freecodecamp.org/curriculum/cat-photo-app/lasagna.jpg" alt="A slice of lasagna on a plate.">
          <figcaption>Cats <em>love</em> lasagna.</figcaption>  
        </figure>
        <h3>Top 3 things cats hate:</h3>
        <ol>
          <li>flea treatment</li>
          <li>thunder</li>
          <li>other cats</li>
        </ol>
        <figure>
          <img src="https://cdn.freecodecamp.org/curriculum/cat-photo-app/cats.jpg" alt="Five cats looking around a field.">
          <figcaption>Cats <strong>hate</strong> other cats.</figcaption>  
        </figure>
       </section>
      </section>
2

Please Tell us what’s happening in your own words.

Learning to describe problems is hard, but it is an important part of learning how to code.

Also, the more you say, the more we can help!