Learn Responsive Web Design by Building a Piano - Step 6

Tell us what’s happening:
Getting error: Your second .key element should also have a class of black--key .

I’ve tried with either one or two spaces, with dashes, changing the order of the classes. none worked. Help

  **Your code so far**
/* file: index.html */
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <title>Piano</title>
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
</head>
<body>
  <div id="piano">
    <div class="keys">
      <div class="key"></div>
      <div class="black  key"></div>
      <div class="black  key"></div>
      <div class="key"></div>
      <div class="black  key"></div>
      <div class="black  key"></div>
      <div class="black  key"></div>
    </div>
  </div>
</body>
</html>
/* file: styles.css */

  **Your browser information:**

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.5112.102 Safari/537.36 OPR/90.0.4480.100

Challenge: Learn Responsive Web Design by Building a Piano - Step 6

Link to the challenge:

The instruction ask you to add and not to replace.

So simply just add another new class and don’t delete the key class

Like (class=“key” class=“black key”) or (class=“key” class="black ")? That doesn’t work either. I’ve read that you can define multiple classes separating the class names with a space and I tried that in the code above but that didn’t work

class=“value anothervalue”
2 value in one quotation in one attribute

That did it. Thank you a lot!

Giving out answer without explanation is not how it works. Should stick to the forum rule as I know.