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---
id: 587d78a8367417b2b2512ae5
title: Animate Elements at Variable Rates
challengeType: 0
videoUrl: 'https://scrimba.com/c/cZ89WA4'
---
## Description
< section id = 'description' >
There are a variety of ways to alter the animation rates of similarly animated elements. So far, this has been achieved by applying an < code > animation-iteration-count< / code > property and setting < code > @keyframes< / code > rules.
To illustrate, the animation on the right consists of two "stars" that each decrease in size and opacity at the 20% mark in the < code > @keyframes< / code > rule, which creates the twinkle animation. You can change the < code > @keyframes< / code > rule for one of the elements so the stars twinkle at different rates.
< / section >
## Instructions
< section id = 'instructions' >
Alter the animation rate for the element with the class name of < code > star-1< / code > by changing its < code > @keyframes< / code > rule to 50%.
< / section >
## Tests
< section id = 'tests' >
```yml
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tests:
- text: The < code > @keyframes</ code > rule for the < code > star-1</ code > class should be 50%.
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testString: assert(code.match(/twinkle-1\s*?{\s*?50%/g), 'The < code > @keyframes</ code > rule for the < code > star-1</ code > class should be 50%.');
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```
< / section >
## Challenge Seed
< section id = 'challengeSeed' >
< div id = 'html-seed' >
```html
< style >
.stars {
background-color: white;
height: 30px;
width: 30px;
border-radius: 50%;
animation-iteration-count: infinite;
}
.star-1 {
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margin-top: 15%;
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margin-left: 60%;
animation-name: twinkle-1;
animation-duration: 1s;
}
.star-2 {
margin-top: 25%;
margin-left: 25%;
animation-name: twinkle-2;
animation-duration: 1s;
}
@keyframes twinkle-1 {
20% {
transform: scale(0.5);
opacity: 0.5;
}
}
@keyframes twinkle-2 {
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 >
< / section >
## Solution
< section id = 'solution' >
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```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-name: twinkle-1;
animation-duration: 1s;
}
.star-2 {
margin-top: 25%;
margin-left: 25%;
animation-name: twinkle-2;
animation-duration: 1s;
}
@keyframes twinkle-1 {
50% {
transform: scale(0.5);
opacity: 0.5;
}
}
@keyframes twinkle-2 {
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 >
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```
< / section >