That's great, but it doesn't work right yet. Notice how the animation resets after <code>500ms</code> has passed, causing the button to revert back to the original color. You want the button to stay highlighted.
This can be done by setting the <code>animation-fill-mode</code> property to <code>forwards</code>. The <code>animation-fill-mode</code> specifies the style applied to an element when the animation has finished. You can set it like so:
<code>animation-fill-mode: forwards;</code>
</section>
## Instructions
<sectionid='instructions'>
Set the <code>animation-fill-mode</code> property of <code>button:hover</code> to <code>forwards</code> so the button stays highlighted when a user hovers over it.
- text: <code>button:hover</code> should have a <code>animation-fill-mode</code> property with a value of <code>forwards</code>.
testString: assert(code.match(/button\s*?:\s*?hover\s*?{[\s\S]*animation-fill-mode\s*?:\s*?forwards\s*?;[\s\S]*}/gi) && code.match(/button\s*?:\s*?hover\s*?{[\s\S]*animation-name\s*?:\s*?background-color\s*?;[\s\S]*}/gi) && code.match(/button\s*?:\s*?hover\s*?{[\s\S]*animation-duration\s*?:\s*?500ms\s*?;[\s\S]*}/gi), '<code>button:hover</code> should have a <code>animation-fill-mode</code> property with a value of <code>forwards</code>.');