Use CSS Animation to Change the Hover State of a Button

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" />

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%.