.k:hover {
  opacity:0.5;
  border:2px;border-style:ridge;border-color:lime;
  border-radius:150px;
  background-color:lime;
  transition:2s;
}


.btncloak {
  background-color:lime;
  border-color:black;
}

.btncloak:hover {
  border-radius:150px;
  transition: 2s;
}