.upper-circle {
  width: 200%;
  height: 850px;
  border-radius: 100%;
  margin-bottom: -720px;
  margin-left: -50%;
}
@media screen and (min-width: 640px) {
  .upper-circle {
    width: 120%;
    margin-left: -10%;
    margin-bottom: -700px;
    height: 1000px;
  }
}