freeCodeCamp/curriculum/challenges/english/01-responsive-web-design/applied-visual-design/animate-multiple-elements-a...

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---
id: 587d78a8367417b2b2512ae6
title: Animate Multiple Elements at Variable Rates
challengeType: 0
videoUrl: 'https://scrimba.com/c/cnpWZc9'
forumTopicId: 301042
dashedName: animate-multiple-elements-at-variable-rates
---
# --description--
In the previous challenge, you changed the animation rates for two similarly animated elements by altering their `@keyframes` rules. You can achieve the same goal by manipulating the `animation-duration` of multiple elements.
In the animation running in the code editor, there are three stars in the sky that twinkle at the same rate on a continuous loop. To make them twinkle at different rates, you can set the `animation-duration` property to different values for each element.
# --instructions--
Set the `animation-duration` of the elements with the classes `star-1`, `star-2`, and `star-3` to 1s, 0.9s, and 1.1s, respectively.
# --hints--
The `animation-duration` property for the star with class `star-1` should remain at 1s.
```js
assert($('.star-1').css('animation-duration') == '1s');
```
The `animation-duration` property for the star with class `star-2` should be 0.9s.
```js
assert($('.star-2').css('animation-duration') == '0.9s');
```
The `animation-duration` property for the star with class `star-3` should be 1.1s.
```js
assert($('.star-3').css('animation-duration') == '1.1s');
```
# --seed--
## --seed-contents--
```html
<style>
.stars {
background-color: white;
height: 30px;
width: 30px;
border-radius: 50%;
animation-iteration-count: infinite;
}
.star-1 {
margin-top: 15%;
margin-left: 60%;
animation-duration: 1s;
animation-name: twinkle;
}
.star-2 {
margin-top: 25%;
margin-left: 25%;
animation-duration: 1s;
animation-name: twinkle;
}
.star-3 {
margin-top: 10%;
margin-left: 50%;
animation-duration: 1s;
animation-name: twinkle;
}
@keyframes twinkle {
20% {
transform: scale(0.5);
opacity: 0.5;
}
}
#back {
position: fixed;
padding: 0;
margin: 0;
top: 0;
left: 0;
width: 100%;
height: 100%;
background: linear-gradient(black, #000099, #66c2ff, #ffcccc, #ffeee6);
}
</style>
<div id="back"></div>
<div class="star-1 stars"></div>
<div class="star-2 stars"></div>
<div class="star-3 stars"></div>
```
# --solutions--
```html
<style>
.stars {
background-color: white;
height: 30px;
width: 30px;
border-radius: 50%;
animation-iteration-count: infinite;
}
.star-1 {
margin-top: 15%;
margin-left: 60%;
animation-duration: 1s;
animation-name: twinkle;
}
.star-2 {
margin-top: 25%;
margin-left: 25%;
animation-duration: 0.9s;
animation-name: twinkle;
}
.star-3 {
margin-top: 10%;
margin-left: 50%;
animation-duration: 1.1s;
animation-name: twinkle;
}
@keyframes twinkle {
20% {
transform: scale(0.5);
opacity: 0.5;
}
}
#back {
position: fixed;
padding: 0;
margin: 0;
top: 0;
left: 0;
width: 100%;
height: 100%;
background: linear-gradient(black, #000099, #66c2ff, #ffcccc, #ffeee6);
}
</style>
<div id="back"></div>
<div class="star-1 stars"></div>
<div class="star-2 stars"></div>
<div class="star-3 stars"></div>
```