Learn CSS Colors by Building a Set of Colored Markers - Step 50

I have this code

/* file: index.html */
<!DOCTYPE html>
<html lang="en">
  <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">
  <h1>CSS Color Markers</h1>
  <div class="container">
    <div class="marker red">
    <div class="marker green">
    <div class="marker blue">
/* 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),rgb(0,127,0));

.green {
background-color: #007F00;

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

But not passed my code

.red {
background:linear-gradient(90deg,rgb(255, 0, 0),rgb(0,127,0));

and request this:

Now you’ll apply a red-to-green gradient along a 90 degree line to the first marker.

First, in the .red CSS rule, set the background property to linear-gradient(), and pass it the value 90deg as the gradientDirection.

then, Which one´s mistake?