Answers for "when hover animation css"

css start animation on hover

button{
  animation: rotate360 1.2s linear infinite;  /* animation set */
  animation-play-state: paused;               /* put paused */
}
button:hover{
  animation-play-state: running;              /* trigger on hover */
}
@keyframes rotate360 {                        /* keyframes of animation */
  to { transform: rotate(360deg); }           
}