Tell us what’s happening:
Describe your issue in detail here.
**Your code so far**
/* file: index.html */
<!DOCTYPE html>
<html>
<head>
<title>City Skyline</title>
<link href="styles.css" rel="stylesheet" type="text/css" />
</head>
<body>
<div class="background-buildings">
<div class="bb1">
<div class="bb1a"></div>
<div class="bb1b"></div>
<div class="bb1c"></div>
<div class="bb1d"></div>
</div>
</div>
</body>
</html>
/* file: styles.css */
* {
border: 1px solid black;
box-sizing: border-box;
}
body {
height: 100vh;
margin: 0;
overflow: hidden;
}
.background-buildings {
width: 100%;
height: 100%;
}
.bb1 {
width: 10%;
height: 70%;
display: flex;
flex-direction: column;
align-items: center;
--building-color1: #999;
}
.bb1a {
width: 70%;
height: 10%;
background-color: var(--background-color1);
}
.bb1b {
width: 80%;
height: 10%;
}
.bb1c {
width: 90%;
height: 10%;
}
.bb1d {
width: 100%;
height: 70%;
}
**Your browser information:**
User Agent is: Mozilla/5.0 (Windows NT 6.1; rv:101.0) Gecko/20100101 Firefox/101.0
Challenge: Step 15
Link to the challenge: