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: