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HTML

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HTML preprocessors can make writing HTML more powerful or convenient. For instance, Markdown is designed to be easier to write and read for text documents and you could write a loop in Pug.

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Adding Classes

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About the <head>

In CodePen, whatever you write in the HTML editor is what goes within the <body> tags in a basic HTML5 template. If you need things in the <head> of the document, put that code here.

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Insecure Resource

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CSS

About CSS Preprocessors

CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.

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CSS Base

About CSS Base

It's a common practice to apply CSS to a page that styles elements such that they are consistent across all browsers. We offer two of the most popular choices: normalize.css and a reset. Or, choose Neither and nothing will be applied.

Vendor Prefixing

About Vendor Prefixing

To get the best cross-browser support, it is a common practice to apply vendor prefixes to CSS properties and values that require them to work. For instance -webkit- or -moz-.

We offer two popular choices: Autoprefixer (which processes your CSS server-side) and -prefix-free (which applies prefixes via a script, client-side).

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You can apply CSS to your Pen from any stylesheet on the web. Just put a URL to it here and we'll apply it, in the order you have them, before the CSS in the Pen itself.

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JavaScript

About JavaScript Preprocessors

JavaScript preprocessors can help make authoring JavaScript easier and more convenient.

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Babel includes JSX processing.

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If the script you link to has the file extension of a preprocessor, we'll attempt to process it before applying.

You can also link to another Pen here, and we'll pull the JavaScript from that Pen and include it. If it's using a matching preprocessor, we'll combine the code before preprocessing, so you can use the linked Pen as a true dependency.

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Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.

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HTML 

              
                <div class="container">
	<svg viewbox="0 0 100 100" class="circle"><circle cx="50" cy="50" r="40" /></svg>
	<svg viewbox="0 0 100 100" class="circle"><circle cx="50" cy="50" r="40" /></svg>
	<svg viewbox="0 0 100 100" class="circle"><circle cx="50" cy="50" r="40" /></svg>
	<svg viewbox="0 0 100 100" class="circle"><circle cx="50" cy="50" r="40" /></svg>
	<svg viewbox="0 0 100 100" class="circle"><circle cx="50" cy="50" r="40" /></svg>
	<svg viewbox="0 0 100 100" class="circle"><circle cx="50" cy="50" r="40" /></svg>
	<svg viewbox="0 0 100 100" class="circle"><circle cx="50" cy="50" r="40" /></svg>
</div>

<div class="playground">
	You can edit the CSS variables yourself.
	</br>
	Or you can select a preset:
	</br>
	<button id="default">Default</button>
	<button id="void">Void</button>
	<button id="random">Random</button>

  <p>
	  Made without coffee by <a href="https://twitter.com/a_sandrina_p" target="_blank" class="link">Sandrina Pereira</a> for her <a href="https://www.sandrina-p.net/" target="_blank">website</a>.
	  <br/>
	  Would you <a href="https://www.buymeacoffee.com/sandrinap" target="_blank" class="link">buy her a coffe</a>?</p>
</div>

<footer class="footer">

</footer>
!

CSS 

              
                body { background: black; height: 100vh; overflow: hidden; }

.container {
	// 🎈 Edit the variables bellow and have fun!
	// TIP: Do it directly on the browser for even more fun
	--size: 35vh;
	--speed: 3s;
	--delay: 150ms;
	--ease: cubic-bezier(.48,0,.48,1);
	--scaleStart: 0.8;
	--scaleEnd: 1;
	--rotate: 30deg;
	--rotatePivot: 2deg;
	--fill: #61fbf424;
	--distance: 20rem;
	position: absolute;
	top: 50%; left: 50%;
	transform: translate(-50%, -50%);
	height: var(--size);
	width: calc(var(--size) + var(--distance));
}

.circle {
	position: absolute;
	top: 0;
	left: 0;
	width: var(--size);
	stroke: white;
	stroke-width: 1;
	fill: var(--fill);
	animation: circleMove var(--speed) var(--ease) infinite alternate-reverse;

	@for $i from 1 through 10 {
		&:nth-child(#{$i}) {
			// [1] - Start in a middle so it's pretty on first render when the animation didn't start yet.
			animation-delay: calc((var(--speed) * -1) - #{-$i} * var(--delay) - 2100ms); // 1
			// animation-play-state: paused; // TIL: use to see exactly the 1st frame
			$dash: 0;
			$gap: 0;
			@if $i > 1 {
				$dash: 10 - $i;
				$gap: $i - 1;	
			}
			stroke-dasharray: $dash, $gap;
			opacity: 1-(1*$i*0.07);
			--rotatePivot: #{$i*3}deg;

			transform:
				translateX(0)
				scale(var(--scaleStart))
				rotate( calc(0deg + var(--rotatePivot)) ); // 1
		}
	}
}

@keyframes circleMove {
	from {
		transform:
			translateX(0)
			scale(var(--scaleStart))
			rotate( calc(0deg + var(--rotatePivot)) );
		filter: drop-shadow(3px 0px 0px rgba(#900, 0.5));
	}
	to {
		transform:
			translateX(var(--distance))
			scale(var(--scaleEnd))
			rotate( calc(var(--rotate) + var(--rotatePivot)) );
		filter: drop-shadow(1px 0px 0px rgba(#900, 0.8));
	}
}

.playground {
	position: absolute;
	bottom: 0; left: 0;
	color: #aaa;
	padding: 1rem;
	width: 100vw;
	font-size: 0.8rem;
	
	button {
		border: 1px solid #aaa;
		background: transparent;
		margin-top: 0.5rem;
		color: #aaa;
		padding: 0.2rem;
		width: 5rem;
		
		&:active,
		&:focus {
			background: #aaa;
			color: black;
		}
	}

	a { color: white; }

}
!

JS 

              
                // No JS needed for the actual animation.
// This is used for "Random" button click.

const container = document.getElementsByClassName('container')[0];

document.getElementById('default').addEventListener('click', () => {
	container.style.setProperty('--size', '')
	container.style.setProperty('--speed', '')
	container.style.setProperty('--delay', '')
	container.style.setProperty('--scaleStart', '')
	container.style.setProperty('--scaleEnd', '')
	container.style.setProperty('--rotate', '')
	container.style.setProperty('--rotatePivot', '')
	container.style.setProperty('--rotatePivot', '')
	container.style.setProperty('--fill', '')
	container.style.setProperty('--distance', '');
});

document.getElementById('void').addEventListener('click', () => {
	container.style.setProperty('--size', '')
	container.style.setProperty('--speed', '4s')
	container.style.setProperty('--delay', '150ms')
	container.style.setProperty('--scaleStart', '0.8')
	container.style.setProperty('--scaleEnd', '-1')
	container.style.setProperty('--rotate', '45deg')
	container.style.setProperty('--rotatePivot', '')
	container.style.setProperty('--fill', '')
	container.style.setProperty('--distance', '');
});

function random(min, max) {
  min = Math.ceil(min);
  max = Math.floor(max);
  return Math.floor(Math.random() * (max - min)) + min;
}

function getAcolor() {
  var letters = '0123456789ABCDEF';
  var color = '#';
  for (var i = 0; i < 6; i++) {
    color += letters[Math.floor(Math.random() * 16)];
  }
  return `${color}AD`; // AD = 80% opacity
}

document.getElementById('random').addEventListener('click', () => {
	container.style.setProperty('--size', `${random(20, 50)}vh`);
	container.style.setProperty('--speed', `${random(3, 6)}s`);
	container.style.setProperty('--delay', `${random(100, 600)}ms`);
	container.style.setProperty('--scaleStart', `${random(-10, 10)/10}`);
	container.style.setProperty('--scaleEnd', `${random(-10, 10)/10}`);
	container.style.setProperty('--rotate', `${random(0, 90)}deg`);
	container.style.setProperty('--rotatePivot', `${random(0, 90)}deg`);
	container.style.setProperty('--distance', `${random(5, 60)}vh`);
	container.style.setProperty('--fill', getAcolor());
});
!
999px

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