css实现椭圆、半椭圆

1. 椭圆

.ellipse{
  width: 250px;
  height: 150px;
  margin: 50px;
  background: #FFD900;
  border-radius: 50% / 50%;
}

2.半椭圆

.ellipse{
  width: 550px;
  height: 150px;
  margin: 50px;
  background: #FFD900;
  border-radius: 50% / 100% 100% 0 0;
}