如何使用CSS实现这种视觉效果

div {
  background-color: red;
  border-radius: 0 0 50% 50%;
  background-image: 
       linear-gradient(-45deg, transparent 75%, blue 75%), 
       linear-gradient(45deg, transparent 75%, yellow 75%), 
       linear-gradient(to top, green 50%, transparent 50%);
  height: 300px;
  width: 300px;
  transition:0.5s;
}
div:hover {
  height: 150px;
  width: 150px;
}
/* fun */

div {
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  font-size: 2.5em;
  color: white;
  text-shadow: 0 0 1px black, 0 0 1px black, 0 0 1px black, 0 0 1px black, 0 0 1px black, 0 0 1px black;
  box-shadow: 0 0 5px gray, inset 0 0 0 3px white,inset 0 0 5px black;
}

<div>Hover me</div>