freeCodeCamp/curriculum/challenges/english/14-responsive-web-design-22/learn-css-variables-by-building-a-city-skyline/5d822fd413a79914d39e98d9.md

---
id: 5d822fd413a79914d39e98d9
title: Step 17
challengeType: 0
dashedName: step-17
---

# --description--

I don't really like that color. Change the value of your variable from `#999` to `#aa80ff` and you can see how it gets applied everywhere you used the variable. This is the main advantage of using variables, being able to quickly change many values in your stylesheet by just changing the value of a variable.

# --hints--

You should change the value of the `--building-color1` property variable from `#999` to `#aa80ff`.

```js
assert.equal(new __helpers.CSSHelp(document).getStyle('.bb1')?.getPropertyValue('--building-color1').trim(),'#aa80ff');
```

# --seed--

## --seed-contents--

```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>
```

```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;
--fcc-editable-region--
  --building-color1: #999;
--fcc-editable-region--
}

.bb1a {
  width: 70%;
  height: 10%;
  background-color: var(--building-color1);
}

.bb1b {
  width: 80%;
  height: 10%;
  background-color: var(--building-color1);
}

.bb1c {
  width: 90%;
  height: 10%;
  background-color: var(--building-color1);
}

.bb1d {
  width: 100%;
  height: 70%;
  background-color: var(--building-color1);
}

```