--description--

You can use CSS @keyframes to change the color of a button in its hover state.

Here's an example of changing the width of an image on hover:

<style>
  img {
    width: 30px;
  }
  img:hover {
    animation-name: width;
    animation-duration: 500ms;
  }

  @keyframes width {
    100% {
      width: 40px;
    }
  }
</style>

<img src="https://cdn.freecodecamp.org/curriculum/applied-visual-design/google-logo.png" alt="Google's Logo" />

--instructions--

Note that ms stands for milliseconds, where 1000ms is equal to 1s.

Use CSS @keyframes to change the background-color of the button element so it becomes #4791d0 when a user hovers over it. The @keyframes rule should only have an entry for 100%.

--hints--

The @keyframes rule should use the animation-name background-color.

assert(code.match(/@keyframes\s+?background-color\s*?{/g));

There should be one rule under @keyframes that changes the background-color to #4791d0 at 100%.

assert(code.match(/100%\s*?{\s*?background-color:\s*?#4791d0;\s*?}/gi));

--seed--

--seed-contents--

<style>
  button {
    border-radius: 5px;
    color: white;
    background-color: #0F5897;
    padding: 5px 10px 8px 10px;
  }

  button:hover {
    animation-name: background-color;
    animation-duration: 500ms;
  }


</style>

<button>Register</button>

--solutions--

<style>
  button {
    border-radius: 5px;
    color: white;
    background-color: #0F5897;
    padding: 5px 10px 8px 10px;
  }

  button:hover {
    animation-name: background-color;
    animation-duration: 500ms;
  }

  @keyframes background-color {
    100% {
      background-color: #4791d0;
    }
  }
</style>
<button>Register</button>