$rings: 30

body
  background-color: #0F0F0F

.tri
  position: absolute
  top: 50%
  left: 50%
  transform: translate(-50%, 100%)
  width: 50px
  height: 50px

  .side
    width: 50px
    height: 50px
    position: absolute
    transform-origin: center center
    @for $i from 1 through 3
      &:nth-child(#{$i})
        transform: translateX(-200px + 100*$i)
    &:nth-child(2)
      transform: translateY(-150px)

  .ring
    width: 50px
    height: 50px
    position: absolute
    background: white
    animation-name: rotate, cromatic
    animation-duration: 3s, 3s
    animation-timing-function: linear, linear
    animation-iteration-count: infinite, infinite
    opacity: 0.5
    box-shadow: 0 0 30px black
    border-radius: 20%
      
@for $i from 0 through $rings
  .side:nth-child(1) .ring:nth-child(#{$i})
    margin: 0 0 0 200/$rings*$i+px
    z-index: $i
    animation-delay: $i/ $rings +s

@for $i from 0 through $rings
  .side:nth-child(2) .ring:nth-child(#{$i})
    margin: 150/$rings*$i+px 0 0 -100/$rings*$i+px
    z-index: $rings - $i
    animation-delay: 2+$i/ $rings +s

@for $i from 0 through $rings
  .side:nth-child(3) .ring:nth-child(#{$i})
    margin: -150/$rings*$i+px 0 0 -100/$rings*$i+px
    z-index: $i
    animation-delay: 1+$i/ $rings +s
      
@keyframes rotate
  to
    transform: rotate(360deg)

@keyframes cromatic
  0%
    background-color: #FFFF00
  15%
    background-color: #008F59
  30%
    background-color: #2771B2
  45%
    background-color: #6E3795
  60%
    background-color: #FF0000
  75%
    background-color: #FF9201
  100%
    background-color: #FFFF00