---
id: 5a9d727a424fe3d0e10cad12
title: Use a custom CSS Variable
challengeType: 0
videoUrl: 'https://scrimba.com/c/cM989ck'
---
## Description
After you create your variable, you can assign its value to other CSS properties by referencing the name you gave it.
background: var(--penguin-skin);
This will change the background of whatever element you are targeting to gray because that is the value of the --penguin-skin
variable.
Note that styles will not be applied unless the variable names are an exact match.
## Instructions
Apply the --penguin-skin
variable to the background
property of the penguin-top
, penguin-bottom
, right-hand
and left-hand
classes.
## Tests
```yml
- text: Apply the --penguin-skin
variable to the background
property of the penguin-top
class.
testString: 'assert(code.match(/.penguin-top\s*?{[\s\S]*background\s*?:\s*?var\s*?\(\s*?--penguin-skin\s*?\)\s*?;[\s\S]*}[\s\S]*.penguin-bottom\s{/gi), ''Apply the --penguin-skin
variable to the background
property of the penguin-top
class.'');'
- text: Apply the --penguin-skin
variable to the background
property of the penguin-bottom
class.
testString: 'assert(code.match(/.penguin-bottom\s*?{[\s\S]*background\s*?:\s*?var\s*?\(\s*?--penguin-skin\s*?\)\s*?;[\s\S]*}[\s\S]*.right-hand\s{/gi), ''Apply the --penguin-skin
variable to the background
property of the penguin-bottom
class.'');'
- text: Apply the --penguin-skin
variable to the background
property of the right-hand
class.
testString: 'assert(code.match(/.right-hand\s*?{[\s\S]*background\s*?:\s*?var\s*?\(\s*?--penguin-skin\s*?\)\s*?;[\s\S]*}[\s\S]*.left-hand\s{/gi), ''Apply the --penguin-skin
variable to the background
property of the right-hand
class.'');'
- text: Apply the --penguin-skin
variable to the background
property of the left-hand
class.
testString: 'assert(code.match(/.left-hand\s*?{[\s\S]*background\s*?:\s*?var\s*?\(\s*?--penguin-skin\s*?\)\s*?;[\s\S]*}/gi), ''Apply the --penguin-skin
variable to the background
property of the left-hand
class.'');'
```
## Challenge Seed
## Solution
```js
var code = ".penguin-top {background: var(--penguin-skin);} .penguin-bottom {background: var(--penguin-skin);} .right-hand {background: var(--penguin-skin);} .left-hand {background: var(--penguin-skin);}"
```