freeCodeCamp/curriculum/challenges/english/01-responsive-web-design/basic-css/cascading-css-variables.eng...

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---
id: 5a9d7295424fe3d0e10cad14
title: Cascading CSS variables
challengeType: 0
videoUrl: 'https://scrimba.com/c/cyLZZhZ'
---
## Description
<section id='description'>
When you create a variable, it becomes available for you to use inside the element in which you create it. It also becomes available within any elements nested within it. This effect is known as <dfn>cascading</dfn>.
Because of cascading, CSS variables are often defined in the <dfn>:root</dfn> element.
<code>:root</code> is a <dfn>pseudo-class</dfn> selector that matches the root element of the document, usually the <code><html></code> element. By creating your variables in <code>:root</code>, they will be available globally and can be accessed from any other selector later in the style sheet.
</section>
## Instructions
<section id='instructions'>
Define a variable named <code>--penguin-belly</code> in the <code>:root</code> selector and give it the value of <code>pink</code>. You can then see how the value will cascade down to change the value to pink, anywhere that variable is used.
</section>
## Tests
<section id='tests'>
```yml
tests:
- text: 'declare the <code>--penguin-belly</code> variable in the <code>:root</code> and assign it to <code>pink</code>.'
testString: 'assert(code.match(/:root\s*?{[\s\S]*--penguin-belly\s*?:\s*?pink\s*?;[\s\S]*}/gi), "declare the <code>--penguin-belly</code> variable in the <code>:root</code> and assign it to <code>pink</code>.");'
```
</section>
## Challenge Seed
<section id='challengeSeed'>
<div id='html-seed'>
```html
<style>
:root {
/* add code below */
/* add code above */
}
body {
background: var(--penguin-belly, #c6faf1);
}
.penguin {
--penguin-skin: gray;
--penguin-beak: orange;
position: relative;
margin: auto;
display: block;
margin-top: 5%;
width: 300px;
height: 300px;
}
.right-cheek {
top: 15%;
left: 35%;
background: var(--penguin-belly, white);
width: 60%;
height: 70%;
border-radius: 70% 70% 60% 60%;
}
.left-cheek {
top: 15%;
left: 5%;
background: var(--penguin-belly, white);
width: 60%;
height: 70%;
border-radius: 70% 70% 60% 60%;
}
.belly {
top: 60%;
left: 2.5%;
background: var(--penguin-belly, white);
width: 95%;
height: 100%;
border-radius: 120% 120% 100% 100%;
}
.penguin-top {
top: 10%;
left: 25%;
background: var(--penguin-skin, gray);
width: 50%;
height: 45%;
border-radius: 70% 70% 60% 60%;
}
.penguin-bottom {
top: 40%;
left: 23.5%;
background: var(--penguin-skin, gray);
width: 53%;
height: 45%;
border-radius: 70% 70% 100% 100%;
}
.right-hand {
top: 0%;
left: -5%;
background: var(--penguin-skin, gray);
width: 30%;
height: 60%;
border-radius: 30% 30% 120% 30%;
transform: rotate(45deg);
z-index: -1;
}
.left-hand {
top: 0%;
left: 75%;
background: var(--penguin-skin, gray);
width: 30%;
height: 60%;
border-radius: 30% 30% 30% 120%;
transform: rotate(-45deg);
z-index: -1;
}
.right-feet {
top: 85%;
left: 60%;
background: var(--penguin-beak, orange);
width: 15%;
height: 30%;
border-radius: 50% 50% 50% 50%;
transform: rotate(-80deg);
z-index: -2222;
}
.left-feet {
top: 85%;
left: 25%;
background: var(--penguin-beak, orange);
width: 15%;
height: 30%;
border-radius: 50% 50% 50% 50%;
transform: rotate(80deg);
z-index: -2222;
}
.right-eye {
top: 45%;
left: 60%;
background: black;
width: 15%;
height: 17%;
border-radius: 50%;
}
.left-eye {
top: 45%;
left: 25%;
background: black;
width: 15%;
height: 17%;
border-radius: 50%;
}
.sparkle {
top: 25%;
left: 15%;
background: white;
width: 35%;
height: 35%;
border-radius: 50%;
}
.blush-right {
top: 65%;
left: 15%;
background: pink;
width: 15%;
height: 10%;
border-radius: 50%;
}
.blush-left {
top: 65%;
left: 70%;
background: pink;
width: 15%;
height: 10%;
border-radius: 50%;
}
.beak-top {
top: 60%;
left: 40%;
background: var(--penguin-beak, orange);
width: 20%;
height: 10%;
border-radius: 50%;
}
.beak-bottom {
top: 65%;
left: 42%;
background: var(--penguin-beak, orange);
width: 16%;
height: 10%;
border-radius: 50%;
}
.penguin * {
position: absolute;
}
</style>
<div class="penguin">
<div class="penguin-bottom">
<div class="right-hand"></div>
<div class="left-hand"></div>
<div class="right-feet"></div>
<div class="left-feet"></div>
</div>
<div class="penguin-top">
<div class="right-cheek"></div>
<div class="left-cheek"></div>
<div class="belly"></div>
<div class="right-eye">
<div class="sparkle"></div>
</div>
<div class="left-eye">
<div class="sparkle"></div>
</div>
<div class="blush-right"></div>
<div class="blush-left"></div>
<div class="beak-top"></div>
<div class="beak-bottom"></div>
</div>
</div>
```
</div>
</section>
## Solution
<section id='solution'>
```js
var code = ":root {--penguin-belly: pink;}"
```
</section>