demo.css

.nav-container {
  width: 150px;
  height: 150px;
  overflow: hidden;
  position: relative;
  border-radius: 50%;
  border: 1px solid red;
  box-shadow: 0 0 5px rgba(255, 0, 0, 0.45);
  transition-property: transform;
  transition-duration: 0.3s;
  transition-timing-function: ease-in-out;
}

.nav-item {
  width: 120px;
  height: 120px;
  position: absolute;
  /* border:1px solid #ccc; */
  cursor: pointer;
}
.nav-item.one {
  z-index: 3;
  left: 53px;
  top: 2px;
  background: #333;
  transform: rotate(30deg);
  border-bottom: 1px solid #fff;
}
.nav-item.two {
  z-index: 5;
  left: -16px;
  top: -16px;
  background: #666;
  border-right: 1px solid #fff;
  border-bottom-right-radius: 30px;
}
.nav-item.three {
  z-index: 2;
  transform: rotate(60deg);
  top: 56px;
  left: 4px;
  background: #999;
  border-left: 1px solid #fff;
}
.nav-mask-three {
  position: absolute;
  z-index: 9;
  width: 110px;
  height: 47px;
  top: 70px;
  left: -24px;
  transform: rotate(-30deg);
  background: #999;
  border-top: 1px solid #fff;
  cursor: pointer;
}
.nav-center {
  position: absolute;
  z-index: 101;
  top: 50%;
  left: 50%;
  width: 60px;
  height: 60px;
  transform: translate(-50%, -50%);
  box-sizing: border-box;
  border: 6px solid #fff;
  background: red;
  border-radius: 90px;
  box-shadow: 0 0 20px 0 rgba(57, 63, 103, 0.4);
  font-size: 0;
  color: #fff;
  line-height: 40px;
  text-align: center;
}