Solution of Use CSS Animation to Change the Hover State of a Button

<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>

https://www.freecodecamp.org/learn/responsive-web-design/applied-visual-design/use-css-animation-to-change-the-hover-state-of-a-button

what issue are you having? what are you trying to do? what is it happening instead? what’s your code? if it is a challenge, please provide the link to the challenge