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CSS

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Add External Scripts/Pens

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HTML

              
                - var n = 2;

input(type='checkbox' id='pause')
label(for='pause') pause animation

section
	.rect

pre
	while n--
		span.token--grad(style=`--i: ${n}`)
			span.token--func repeating-linear-gradient
			span.token--punc (
			span.token--args
				span.token--arg
					span.token--ang
						span.token--num #{Math.pow(-1, n + 1)*60}
						span.token--unit deg
				span.token--punc ,
				|  
				span.token--arg
					span.token--stop
						span.token--col transparent
						|  
						span.token--pos 0
				span.token--punc ,
				|  
				span.token--arg
					span.token--stop
						span.token--col transparent
						|  
						span.token--pos
							span.token--num 5
							span.token--unit px
				span.token--punc ,
				|  
				span.token--arg
					span.token--stop
						span.token--col tan
						|  
						span.token--pos 0
				span.token--punc ,
				|  
				span.token--arg
					span.token--stop
						span.token--col tan
						|  
						span.token--pos
							span.token--num 35
							span.token--unit px
			span.token--punc )
		
              
            
!

CSS

              
                $lh: 1.75;
$m: .5em;
$p: .75em;
$t: 10s;
$k: 10%;
$bg: #111;
$d: 1em;
$x0: 40%;
$x1: 100% - $x0;
$x2: 7%;
$x3: 100% - $x2;

*, :before, :after {
	--s: calc(1 - 2*var(--i));
	margin: 0;
	padding: 0;
	font: inherit;
	animation-play-state: inherit !important
}

body {
	--m: 1;
	--h: calc(var(--m)*#{$lh}*1em);
	display: flex;
	flex-direction: column;
	overflow: hidden;
	height: 100vh;
	background: #ddd;
	font: 1em/ #{$lh} consolas, monaco, monospace;
	
	@media (max-width: 760px) {
		--m: 2;
		
		.token--arg:nth-child(3):before {
			content: '\A   '
		}
	}

	@media (max-width: 475px) {
		--m: 3;
		
		.token--arg:nth-child(5n + 2):before {
			content: '\A   '
		}
	}
	
	@media (max-width: 320px) { font-size: .75em }
	
	@media (max-width: 240px) { font-size: .5em }
}

input[type='checkbox'] {
	position: absolute;
	transform: translate(-100vw);
	
	+ label {
		position: absolute;
		z-index: 1;
		margin: $p;
		border: solid 2px $bg;
		padding: $p;
		width: $d; height: $d;
		border-radius: 5px;
		background: #FF667A;
		text-indent: -100vw;
		cursor: pointer;
		transition: .5s;
		
		&:before {
			position: absolute;
			top: .5*$p; right: .5*$p; bottom: .5*$p; left: .5*$p;
			background: #000;
			clip-path: polygon($x0 $x2, $x0 $x3, $x2 $x3, $x2 $x2, $x1 $x2, $x3 $x2, $x3 $x3, $x1 $x3, $x1 $x2);
			transition: inherit;
			content: ''
		}
	}
	
	&:checked {
		+ label {
			background: #85EDB0;
			
			&:before {
				clip-path: polygon(50% + $x2 25%, 50% + $x2 75%, 2*$x2 100%, 2*$x2 0, 50% + $x2 25%, 100% 50%, 100% 50%, 50% + $x2 75%, 50% + $x2 25%)
			}
		}
		
		& ~ * { animation-play-state: paused !important }
	}
}

section {
	display: flex;
	align-items: center;
	justify-content: center;
	flex: 1
}

.rect {
	flex: 1;
	position: relative;
	margin: $m;
	border: dashed 4px #95a;
	max-width: 50em;
	height: calc(100% - 2*#{$m});
	max-height: 30em;
	animation: rect $t linear infinite;
	
	&:before, &:after {
		--i: 0;
		position: absolute;
		top: 0; right: 0; bottom: 0; left: 0;
		background: 
			//linear-gradient(gold 50%, deeppink 0), 
			var(--g0);
		animation: grad0 $t linear infinite;
		content: ''
	}
	
	&:after {
		--i: 1;
		background: var(--g1);
		animation-name: grad1
	}
}

pre {
	display: flex;
	flex-direction: column-reverse;
	align-items: flex-start;
	justify-self: end;
	padding: $p;
	background: linear-gradient($bg, $bg) 0/ 100% no-repeat;
	color: #ddd;
	animation: code $t linear infinite
}

span { display: inline; }

.token {
	&--grad {
		--xm: calc(50vw - #{$p} - 50%);
		--ym: calc(var(--h) + .5*(1 - var(--i))*100% - #{$p} - 50vh);
		box-shadow: 0 0 0 $p $bg;
		background: $bg;
		animation: text0 $t linear infinite;
	
		* + &:after {
			animation: inherit;
			animation-name: comma;
			content: ', '
		}
		
		* + & { animation-name: text1 }
	}

	&--func { color: #d285de }

	&--punc { color: #ff667a }

	&--ang { color: #66c7ff }

	&--col { color: #ffeb66 }

	&--pos { color: #85edb0 }
}

@keyframes rect {
	0%, #{2*$k} { transform: translatey(var(--h)) }
	#{3*$k}, #{6*$k} { transform: translatey(calc(.5*var(--h))) }
	#{7*$k}, 100% { transform: none }
}

@keyframes grad0 {
	0% { transform: translate(calc(var(--s)*-100vw)) }
	#{$k}, 100% { transform: none }
}

@keyframes grad1 {
	0%, #{4*$k} { transform: translate(calc(var(--s)*-100vw)) }
	#{5*$k}, 100% { transform: none }
}

@keyframes code {
	0%, #{3*$k} { background-position: -100vw var(--h) }
	#{4*$k}, #{6*$k} { background-position: 0 var(--h) }
	#{7*$k}, 100% { background-position: 0 }
}

@keyframes text0 {
	0% {
		transform: translate(calc(var(--s)*100vw + var(--xm)), var(--ym))
	}
	#{$k}, #{2*$k} {
		transform: translate(var(--xm), var(--ym))
	}
	#{3*$k}, 100% {
		transform: none
	}
}

@keyframes comma {
	0%, #{6*$k} { opacity: 0 }
	#{7*$k}, 100% { opacity: 1 }
}

@keyframes text1 {
	0%, #{4*$k} {
		transform: translate(calc(var(--s)*100vw + var(--xm)), var(--ym))
	}
	#{5*$k}, #{6*$k} {
		transform: translate(var(--xm), var(--ym));
	}
	#{6.625*$k} {
		box-shadow: 0 0 0 $p $bg;
	}
	#{7*$k}, 100% {
		transform: none;
		box-shadow: 0 0 transparent;
	}
}
              
            
!

JS

              
                [...document.querySelectorAll('.token--grad')].forEach((c, i) => document.body.style.setProperty(`--g${i}`, c.textContent));
              
            
!
999px

Console