Learn CSS Colors by Building a Set of Colored Markers - Step 51

Step 51

You’ll use the rgb function for the colors of this gradient.

In the linear-gradient function, use the rgb function to set the first color argument to pure red.
Describe your issue in detail here. compared my own code to the CSS file shown below character by character and cannot find a mistake or typo.

.red {
background: linear-gradient(90deg rgb(255, 0, 0));
}
the help area shows the exact same thing in my code!
what am I doing wrong?

<!-- 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>Colored Markers</title>
    <link rel="stylesheet" href="styles.css">
  </head>
  <body>
    <h1>CSS Color Markers</h1>
    <div class="container">
      <div class="marker red">
      </div>
      <div class="marker green">
      </div>
      <div class="marker blue">
      </div>
    </div>
  </body>
</html>
/* file: styles.css */
h1 {
  text-align: center;
}

.container {
  background-color: rgb(255, 255, 255);
  padding: 10px 0;
}

.marker {
  width: 200px;
  height: 25px;
  margin: 10px auto;
}

.red {
  background: linear-gradient(90deg rgb(255, 0, 0));
}

.green {
  background-color: #007F00;
}

.blue {
  background-color: hsl(240, 100%, 50%);
}

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:105.0) Gecko/20100101 Firefox/105.0

Challenge: Learn CSS Colors by Building a Set of Colored Markers - Step 51

Link to the challenge:

Missed coma between 90deg and rgb

Thank you very much, I was seriously stuck.