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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

In CodePen, whatever you write in the HTML editor is what goes within the <body> tags in a basic HTML5 template. So you don't have access to higher-up elements like the <html> tag. If you want to add classes there that can affect the whole document, this is the place to do it.

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-.

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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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HTML 

              
                <nav class="focus-within-variant">
	<ul>
		<li><a href="">Vorspeise</a></li>
		<li>
			<a href="">Hauptgericht</a>
			<ul>
				<li><a href="">Hauptgericht mit&nbsp;Fleisch</a></li>
				<li><a href="">Hauptgericht vegetarisch</a></li>
			</ul>
		</li>
		<li><a href="">Dessert</a></li>
	</ul>
</nav>
<p>Dieses Menü wurde ohne JavaScript zubereitet. Als Zutat wurde <code>:focus-within</code> verwendet; Gäste mit <s>Edge oder gar</s> Internet Explorer schauen also in die Röhre.</p>
<p>Das Menü ist für JS-Allergiker geeignet; es schmeckt bloß nicht. Vom Hauptgericht kommt man nicht zum Dessert, sondern man muss das Untermenü über sich ergehen lassen.</p>
<p>Das Menü ist nicht für kleine Tische geeignet. Wenn es nicht in eine Zeile passt, kommt man vom Hauptgericht nicht ins Untermenü.</p>

<nav class="focus-within-variant">
	<ul>
		<li><a href="">Vorspeise</a></li>
		<li tabindex="0">
			Hauptgericht
			<ul>
				<li><a href="">Hauptgericht mit&nbsp;Fleisch</a></li>
				<li><a href="">Hauptgericht vegetarisch</a></li>
			</ul>
		</li>
		<li><a href="">Dessert</a></li>
	</ul>
</nav>
<p>Im Unterschied zu oben ist das Hauptgericht hier kein Link. Damit das Menü tastaturbedienbar ist, trägt das <code>li</code>-Element das Attribut <code>tabindex="0"</code>. Ansonsten gilt das oben Gesagte.</p>
<p>Mit JavaScript könnte man noch dafür sorgen, dass beim Aufklappen des Untermenüs der erste Untermenüpunkt den Fokus erhält. Aber wenn schon JavaScript, dann kann man’s auch gleich richtig machen …</p>

<nav class="button-variant">
	<ul>
		<li><a href="">Vorspeise</a></li>
		<li>
			<button aria-expanded="false">Hauptgericht</button>
			<ul>
				<li><a href="">Hauptgericht mit&nbsp;Fleisch</a></li>
				<li><a href="">Hauptgericht vegetarisch</a></li>
			</ul>
		</li>
		<li><a href="">Dessert</a></li>
	</ul>
</nav>
<p>Das Hauptgericht ist hier ein Button (<code>&lt;button&gt;</code>), der per JavaScript die Sichtbarkeit des Untermenüs steuert – über das <code>aria-expanded</code>-Attribut zur barrierefreien Bedienung.

<nav class="button-variant">
	<ul>
		<li><a href="">Vorspeise</a></li>
		<li>
			<a href="">Hauptgericht</a>
			<button aria-expanded="false">
				<span visually-hidden="true">Untermenü Hauptgericht</span>
			</button>
			<ul>
				<li><a href="">Hauptgericht mit&nbsp;Fleisch</a></li>
				<li><a href="">Hauptgericht vegetarisch</a></li>
			</ul>
		</li>
		<li><a href="">Dessert</a></li>
	</ul>
</nav>
<p>Hier ist das Hauptgericht wieder ein Link. Es sind zwei getrennte UI-Elemente: der Link und der Button zum Öffnen/Schließen des Untermenüs.</p>
<p>Bei den unteren Menüs fehlen noch Zutaten:</p>
<ul>
	<li>Das Untermenü sollte sich beim Verlassen schließen.</li>
	<li>Das Untermenü sollte sich per Esc-Taste schließen.</li>
</ul>
<p>(Die Liste erhebt keinen Anspruch auf Vollständigkeit.)</p>
!

CSS 

              
                body
{
	margin: 0;
	padding-bottom: 4em;
	font-family: Calibri, sans-serif;
	line-height: 1.5;
}

nav
{
	--background-color: hsl(-10deg 80% 40%);
	--text-color: white;
	background-color: var(--background-color);
	color: var(--text-color);
	box-shadow: 0 0.1em 0.1em black;
	font-family:  Didot, serif;
	font-size: 1.25em;
	line-height: 1.25;
}

nav ul
{
	list-style: none;
	// Safari hack, see https://www.scottohara.me/blog/2019/01/12/lists-and-safari.html
	list-style: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg'/%3E");
	margin: 0;
	padding: 0;
	display: flex;
	flex-wrap: wrap;
}

nav ul ul
{
	display: none;
	position: absolute;
	left: 0;
	top: 100%;
	background-color: var(--background-color);
	box-shadow: 0 0.1em 0.1em 0em black;
	z-index: 1;
	font-size: 0.9em;
}

nav.focus-within-variant li:focus-within ul
{
	display: block;
}

nav [aria-expanded="true"] + ul
{
	display: block;
}

nav li:hover ul
{
	display: block;
}

[aria-expanded]
{
	padding-right: 2em;
	background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1 1'%3E%3Cpath d='M0.3,0.1 0.3,0.9 0.8,0.5z' fill='white'/%3E%3C/svg%3E");
	background-position: right 1em center;
	background-size: 0.8em 0.8em;
	background-repeat: no-repeat;
}

[aria-expanded="true"]
{
	background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1 1'%3E%3Cpath d='M0.1,0.3 0.9,0.3 0.5,0.8z' fill='white'/%3E%3C/svg%3E");
}

nav li
{
	padding: 0.25em 1em;
	position: relative;
}

nav a,
nav button
{
	display: inline-block;
	color: currentColor;
	text-decoration: none;
	margin: -0.25em -1em;
	padding: 0.25em 1em;
}

nav button
{
	background-color: transparent;
	background-color: var(--background-color);
	border: none;
	font: inherit;
}

nav a + button
{
	margin-left: 0;
	padding-left: 0;
	width: 1em;
	height: 1.75em;
	vertical-align: text-top;
}

nav a:hover
{
	background-color: hsl(-10deg 75% 50%);
}

nav a:focus,
nav button:focus
{
	background-color: black;
	outline: none;
}

:is(p, ul)
{
	margin: 1em 1em 4em;
	max-width: 36em;
}

:is(p, ul) + :is(p, ul)
{
	margin-top: -4em;
}

code
{
	font-family: Fira Mono, monospace;
}

visually-hidden,
.visually-hidden,
[visually-hidden="true"]
{
	position: absolute !important;
	clip: rect(1px, 1px, 1px, 1px) !important;
	padding: 0 !important;
	border: 0 !important;
	height: 1px !important;
	width: 1px !important;
	overflow: hidden !important;
}
!

JS 

              
                document.documentElement.addEventListener('click', event => {
	if (event.target.tagName == 'BUTTON' && event.target.hasAttribute('aria-expanded'))
	{
		event.target.setAttribute('aria-expanded', event.target.getAttribute('aria-expanded') != 'true');
	}
});

document.documentElement.lang = 'de';
!
999px

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