Shrinking header on scroll without Javascript

index.html

<!-- Sticky header -->
<header class="header-outer">
	<div class="header-inner responsive-wrapper">
		<div class="header-logo">
			<img src="https://assets.codepen.io/285131/acme-2.svg" />
		</div>
		<nav class="header-navigation">
			<a href="#">Home</a>
			<a href="#">About</a>
			<a href="#">Blog</a>
			<a href="#">Contact Us</a>
			<button>Menu</button>
		</nav>
	</div>
</header>
<!-- Content -->
<main class="main">
	<div class="main-content responsive-wrapper">
		<article class="widget">
			<h2>How does it work without JS? 🤯</h2>
			<p>This sticky header consists of two elements: an <strong>outer</strong> and an <strong>inner</strong> container. The outer container is taller than the inner — and the inner is centered vertically.
			<p>By utilizing the <code>position: sticky</code> property <strong>twice</strong>, both on the header's <strong>outer container</strong> and <strong>inner container</strong> the outer container will stick to the <code>body</code>, while the inner container will stick to the outer container.</p>
			<p>Note that the outer container has a negative <code>top</code> value equal to the height difference between the two containers. This causes the outer container to stick <strong>above</strong> the <code>body</code>, making the inner container stick to the "ceiling" on scroll.
			<p></p>
		</article>
	</div>
</main>

script.js

// No JS 🎉

shrinking-header-on-scroll-without-javascript.markdown

Shrinking header on scroll without Javascript

Demonstrating how you can achieve a shrinking, sticky header on scroll without Javascript. Pure CSS, baby.

A Pen by Håvard Brynjulfsen on CodePen.

License.

style.css

@import url("https://fonts.googleapis.com/css2?family=DM+Sans:wght@400;500;700&display=swap");

*,
*:after,
*:before {
	box-sizing: border-box;
}

:root {
	--header-outer-height: 110px;
	--header-inner-height: 70px;
	--header-height-difference: calc(
		var(--header-outer-height) - var(--header-inner-height)
	);
	--header-bg: #fff;
}

body {
	font-family: "DM Sans", sans-serif;
	background-color: #f2f5f7;
	line-height: 1.5;
	min-height: 300vh;
	position: relative;
}

.responsive-wrapper {
	width: 90%;
	max-width: 1280px;
	margin-left: auto;
	margin-right: auto;
}

/* Sticky header */
.header-outer {
	/* Make it stick */
	height: var(--header-outer-height);
	position: sticky;
	top: calc(
		var(--header-height-difference) * -1
	); /* Multiply by -1 to get a negative value */
	display: flex;
	align-items: center;

	/* Other */
	background-color: var(--header-bg);
	box-shadow: 0 2px 10px 0 rgba(0,0,0, 0.1);
}

.header-inner {
	/* Make it stick */
	height: var(--header-inner-height);
	position: sticky;
	top: 0;

	/* Other */
	display: flex;
	align-items: center;
	justify-content: space-between;
}

/* Styling of other elements */
.header-logo img {
	display: block;
	height: calc(var(--header-inner-height) - 30px);
}

.header-navigation {
	display: flex;
	flex-wrap: wrap;
}

.header-navigation a,
.header-navigation button {
	font-size: 1.125rem;
	color: inherit;
	margin-left: 1.75rem;
	position: relative;
	font-weight: 500;
}

.header-navigation a {
	display: none;
	font-size: 1.125rem;
	color: inherit;
	text-decoration: none;
}

.header-navigation button {
	border: 0;
	background-color: transparent;
	padding: 0;
}

.header-navigation a:hover:after,
.header-navigation button:hover:after {
	transform: scalex(1);
}

.header-navigation a:after,
.header-navigation button:after {
	transition: 0.25s ease;
	content: "";
	display: block;
	width: 100%;
	height: 2px;
	background-color: currentcolor;
	transform: scalex(0);
	position: absolute;
	bottom: -2px;
	left: 0;
}

.main {
	margin-top: 3rem;
}

.widget {
	width: 100%;
	max-width: 600px;
	border-radius: 8px;
	box-shadow: 0 15px 30px 0 rgba(0,0,0, 0.1);
	background-color: #fff;
	padding: 2.5rem;
	margin-left: auto;
	margin-right: auto;
	margin-bottom: 2rem;
	font-size: 1.125rem;
}

.widget > * + * {
	margin-top: 1.25em;
}

.widget h2 {
	font-size: 1.5rem;
	font-weight: 700;
	line-height: 1.25;
}

.widget code {
	display: inline-block;
	padding: 0.125em 0.25em;
	border-radius: 2px;
	background-color: #bee5d3;
}

.widget strong {
	font-weight: 700;
}

@media (min-width: 800px) {
	.header-navigation a {
		display: inline-block;
	}

	.header-navigation button {
		display: none;
	}
}