Adding an html selector

How do i add a html selctor

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

      <div class="key"></div>
      <div class="key black--key"></div>
      <div class="key black--key"></div>
      <div class="key"></div>
      <div class="key black--key"></div>
      <div class="key black--key"></div>
      <div class="key black--key"></div>

      <div class="key"></div>
      <div class="key black--key"></div>
      <div class="key black--key"></div>
      <div class="key"></div>
      <div class="key black--key"></div>
      <div class="key black--key"></div>
      <div class="key black--key"></div>
    </div>
  </div>
</body>
</html>
/* file: styles.css */
* {
box-sizing:border-box;
}
  **Your browser information:**

User Agent is: Mozilla/5.0 (Linux; Android 8.0.0; SM-G935U) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Mobile Safari/537.36

Challenge: Step 9

Link to the challenge:

html selectors look like this:

html{
...
}

just insert your properties in there and it should work.