Background color class not working

Español HTML-CSS
1

I did create the silver-background class, I asigned it to the div element but it still not working and idk what to do

  **Tu código hasta el momento**


<link href="https://fonts.googleapis.com/css?family=Lobster" rel="stylesheet" type="text/css">
<style>
.red-text {
  color: red;
}

h2 {
  font-family: Lobster, monospace;
}

p {
  font-size: 16px;
  font-family: monospace;
}

.thick-green-border {
  border-color: green;
  border-width: 10px;
  border-style: solid;
  border-radius: 50%;
}

.silver-background {
background-color: silver;
}

.smaller-image {
  width: 100px;
}
</style>

<h2 class="red-text">CatPhotoApp</h2>
<main>
<p class="red-text">Click here to view more <a href="#">cat photos</a>.</p>

<a href="#"><img class="smaller-image thick-green-border" src="https://cdn.freecodecamp.org/curriculum/cat-photo-app/relaxing-cat.jpg" alt="A cute orange cat lying on its back."></a>
<div class:"silver-background">
  <p>Things cats love:</p>
  <ul>
    <li>cat nip</li>
    <li>laser pointers</li>
    <li>lasagna</li>
  </ul>
  <p>Top 3 things cats hate:</p>
  <ol>
    <li>flea treatment</li>
    <li>thunder</li>
    <li>other cats</li>
  </ol>
</div>

<form action="https://freecatphotoapp.com/submit-cat-photo">
  <label><input type="radio" name="indoor-outdoor" checked> Indoor</label>
  <label><input type="radio" name="indoor-outdoor"> Outdoor</label><br>
  <label><input type="checkbox" name="personality" checked> Loving</label>
  <label><input type="checkbox" name="personality"> Lazy</label>
  <label><input type="checkbox" name="personality"> Energetic</label><br>
  <input type="text" placeholder="cat photo URL" required>
  <button type="submit">Submit</button>
</form>
</main>

  **Información de tu navegador:**

El agente de usuario es: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.81 Safari/537.36 OPR/80.0.4170.61

Desafío: Establece el color de fondo de un elemento div

Enlaza al desafío:

2

The error message reads;
Tu elemento div debe incluir la “class” silver-background.
Tu elemento div debe tener un color de fondo “silver” (plateado).

You have a typo here;
<div class:"silver-background">

Do you remember how to assign the value to the class attribute?

3

In the div you use ‘:’, But you must use ‘=’