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CSS

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JavaScript

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HTML 

              
                <h1>CSS <code>light-dark()</code> demo</h1>
<div class="warning"><p>Your browser does not support <code>light-dark()</code> so this demo will not work properly. Try Firefox 120+</p></div>
<h2>CSS Used</h2>
<pre><code>#demo {
	color-scheme: light dark;
	
	.dark {
		color-scheme: dark;
	}

	.light {
		color-scheme: light;
	}
	
	& div {
		background: light-dark(#d4d4d4, #000);
		color: light-dark(#333, #ccc);
	}
}</code></pre>

<h2>Live Output</h2>

<main>
	<div id="demo">
		<div class="auto">
			<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Quae soluta nobis deserunt hic sed. Neque iure saepe earum quis fugiat ipsa repudiandae tempore, culpa autem laborum doloribus ratione officia at?</p>
		</div>

		<div class="dark">
			<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Quae soluta nobis deserunt hic sed. Neque iure saepe earum quis fugiat ipsa repudiandae tempore, culpa autem laborum doloribus ratione officia at?</p>

			<div class="light">
				<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Quae soluta nobis deserunt hic sed. Neque iure saepe earum quis fugiat ipsa repudiandae tempore, culpa autem laborum doloribus ratione officia at?</p>

				<div class="auto">
					<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Quae soluta nobis deserunt hic sed. Neque iure saepe earum quis fugiat ipsa repudiandae tempore, culpa autem laborum doloribus ratione officia at?</p>
				</div>
			</div>

			<div class="auto">
				<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Quae soluta nobis deserunt hic sed. Neque iure saepe earum quis fugiat ipsa repudiandae tempore, culpa autem laborum doloribus ratione officia at?</p>
			</div>
		</div>

		<div class="auto">
			<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Quae soluta nobis deserunt hic sed. Neque iure saepe earum quis fugiat ipsa repudiandae tempore, culpa autem laborum doloribus ratione officia at?</p>
		</div>
	</div>
</main>

<footer>
	<p>Demo for <a href="https://brm.us/light-dark" target="_top">https://brm.us/light-dark</a></p>
</footer>
!

CSS 

              
                @layer reset, layout;

#demo {
	color-scheme: light dark;
	
	.dark {
		color-scheme: dark;
	}

	.light {
		color-scheme: light;
	}
	
	.auto {
		color-scheme: light dark;
	}
	
	& div {
		border: 1px solid #ccc;
		padding: 1em;
		margin: 1em;
		
		&[class] {
			position: relative;
			padding-top: 1.8em;
			
			&::before {
				content: "." attr(class);
				position: absolute;
				top: 0;
				left: 0;
				font-size: 0.8rem;
				padding: 0.3em;
				background: #e4e4e4;
				color: #333;
				font-weight: normal;
				font-family: monospace;
			}
		}
	}
	
	& div {
		background: light-dark(#d4d4d4, #000);
		color: light-dark(#333, #ccc);
	}
}

@supports(color: light-dark(black, white)) {
	.warning {
		display: none;
	}
}

@layer layout {
	@layer general {
		body {
			padding: 3rem 0 2rem;
			width: 90%;
			max-width: 60em;
			margin: 0 auto;
		}
		body > footer {
			text-align: center;
			margin: 2rem 0;
			font-style: italic;
		}
 	}
	@layer visualization {
		body > main {
			margin: 2rem auto;
		}
		body > main [data-identifier] {
			position: relative;
			padding: 1.8rem 1.2rem;
			border: 2px solid #ccc;
			margin: 0.5rem 0 0 0;
		}
		body > main [data-identifier]::before {
			content: '<' attr(data-identifier) '>';
			position: absolute;
			top: 0;
			left: 0;
			font-size: 0.8rem;
			padding: 0.3em;
			background: #e4e4e4;
			color: #333;
			font-weight: normal;
			font-family: monospace;
		}

		main img {
			max-height: 0px;
			width: auto;
		}

		main span.img {
			display: inline-block;
		}
	}
	
	@layer warning {
		/* Show warning for browsers without support */
		.warning {
			padding: 1em;
			border: 1px solid black;
			z-index: 9999;
			color: black;
			background: rgba(255 255 225 / 0.9);
			z-index: 10001;
			
			width: 100%;
			margin: 1em auto;
			text-align: center;
		}
		
		:is(
			.warning:hover,
			.warning:has(:focus-within)
		) {
			opacity: 1;
		}

		.warning > :first-child {
			margin-top: 0;
		}

		.warning > :last-child {
			margin-bottom: 0;
		}

		.warning a {
			color: blue;
		}

		.warning--info {
			border: 1px solid #123456;
			background: rgba(205 230 255 / 0.8);
		}
	}
	
	@layer code {
		pre {
			border: 1px solid #dedede;
			padding: 1em;
			background: #f7f7f7;
			font-family: "Courier 10 Pitch", Courier, monospace;
			overflow-x: auto;
			border-left: 0.4em solid cornflowerblue;
			tab-size: 4;
		}
		
		code:not(pre code), /* output:not(code:has(output) output) */ {
			background: #f7f7f7;
			border: 1px solid rgb(0 0 0 / 0.2);
			padding: 0.1rem 0.3rem;
			margin: 0.1rem 0;
			border-radius: 0.2rem;
			display: inline-block;
		}
	}
}

@layer reset {
	* {
		margin: 0;
		padding: 0;
		box-sizing: border-box;
	}
	html {
		line-height: 1;
	}
	h1, h2, h3, h4 {
		margin: 2em 0 0.5em;
	}
}
!

JS
!
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