$colors: #F4C3D1, #E4A1BD, #D17FA8, #BA6090, #954B76, #743562, #5A2C56, #54214F, #461B46, #320F3B, #2C0A37, #250831;
$r-start: 30px;
$r-fade: 250px;

/* --------------------------------- 
  Mixins 
--------------------------------- */
%center-align {
  -webkit-transform: translate(-50%, -50%);
  -ms-transform: translate(-50%, -50%);
  transform: translate(-50%, -50%);
}

@mixin animation($name, $time) {
  -webkit-animation: $name $time infinite;
     -moz-animation: $name $time infinite;
       -o-animation: $name $time infinite;
          animation: $name $time infinite;
}

@mixin keyframes($name) {
  @-webkit-keyframes #{$name} {
    @content; 
  }
  @-moz-keyframes #{$name} {
    @content;
  }
  @-ms-keyframes #{$name} {
    @content;
  }
  @keyframes #{$name} {
    @content;
  } 
}

#moon {
  position: absolute;
  fill: #FCF8F4;
  fill-rule: evenodd;
  width: 20px;
  height: 20px;
  left: 50%;
  top: 50%;
  @extend %center-align;
}

/* --------------------------------- 
  Circles 
--------------------------------- */
.circle {
  width: $r-start;
  height: $r-start;
  border-radius: 50%;
  background-color: nth($colors, 1);
  position: absolute;
  opacity: 0;
  left: 50%;
  top: 50%;
  @extend %center-align;
  box-shadow: 0 0 2px rgba(0,0,0,0.1);
}

@for $i from 0 through 11 {
  .circle:nth-child(#{11}n+#{$i}) {
    @include animation(undulate, 5s);
    -webkit-animation-delay: $i * 500ms;
            animation-delay: $i * 500ms;
  }
}


/* --------------------------------- 
  Animation 
--------------------------------- */
@include keyframes(undulate) {
  0% {
    width: $r-start;
    height: $r-start;
    opacity: 1;
  }
  
  @for $i from 1 through length($colors) {
    $percent: 7% + 7 * $i;
    
    #{$percent} { background-color: nth($colors, $i); }
  }

  100% {
    background-color: #150525;
    width: $r-fade;
    height: $r-fade;
    opacity: 0;
  }
}

/* --------------------------------- 
  Global 
--------------------------------- */
html,
body {
	padding: 0;
	margin: 0;
	width: 100%;
	height: 100%;
	overflow: hidden;
  background-color: #150525;
}