css彩虹

.f111 {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    box-shadow: 0 0 0 5px inset red, 
                0 0 0 10px inset orange, 
                0 0 0 15px inset yellow, 
                0 0 0 20px inset lime, 
                0 0 0 25px inset aqua, 
                0 0 0 30px inset blue, 
                0 0 0 35px inset magenta;
    clip-path: polygon(0 0, 100%0, 100% 50%, 0 50%);
  }