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HTML 

              
                <header>
    <div class="clamp">
      <a href="#main">Skip to main content</a>
    </div>
      <nav aria-label"Article related">
        <div class="clamp">
          <a href="https://codepen.io/Moiety/pen/dyWPJbz?editors=1100" aria-current="true">View on CodePen</a>
          <a href="https://twitter.com/ZoeBijl">Zoë on Twitter</a>
        </div>
      </nav>
  </header>

  <div class="layout">
    <main id="main" tabindex="-1">
        <header>
          <h1>Short note on skip links with sticky headers</h1>
          <time datetime="2021-07-02"><span>Updated on </span>2nd of July 2021</time>
        </header>
        <p>TL;DR Prevent your sticky header from obscuring your main content with some <code>scroll-padding</code> on the <code>&lt;html&gt;</code> element.</p>
        
        <figure>
            <img src="https://assets.codepen.io/154571/before.png" alt="">
            <figcaption>What we want to prevent: our heading being chopped in half by our sticky header.</figcaption>
        </figure>
       
        <aside>
            <h2>Table of contents</h2>
            <p>(These are also skip links!)</p>
            <ul>
                <li>
                    <a href="#skip link">What is a skip link?</a>
                </li>
                <li>
                    <a href="#sticky-headers">How to make skip links work with sticky headers</a>
                </li>
                <li>
                    <a href="#support">Browser Support</a>
                </li>
                <li>
                    <a href="#resources">Related resources</a>
                </li>
            </ul>
        </aside>
        
        <section id="skip link" aria-labelledby="skip link-heading" tabindex="-1">
            <h2 id="skip link-heading">What is a skip link?</h2>

            <p>
              A skip link lets keyboard users skip over groups of interactive elements.
              You can try this yourself on a lot of pages around the web—this one included!
              If you load <a href="https://cdpn.io/Moiety/debug/dyWPJbz">this Pen in debug mode</a> and press the <kbd>Tab</kbd> key,
              your focus will be set to a skip link titled “Skip to main content”.
              Activating this link will move your focus to the main content and past the links in the navigation bar,
              no extra presses needed!
            </p>
            
            <figure class="note">
              <figcaption>
                Note: If you’re on macOS,
                you might need to enable “<a href="https://www.a11yproject.com/posts/2017-12-29-macos-browser-keyboard-navigation/">Use keyboard navigation</a>” before you’re be able to focus controls
                (such as skip links)
              </figcaption>
              
              <div class="split">
                <img src="https://assets.codepen.io/154571/macOS-keyboard-settings.png" alt="macOS Settings, Keyboard, Shortcuts, Use keyboard navigation to move between controls">
                <img src="https://assets.codepen.io/154571/safari-settings.png" alt="Safari Preferences, Advanced, 'Press tab to highlight elements' indicated">
              </div>
            </figure>
            
            <p>
              Websites use this technique to make life a little bit easier for people who rely on keyboards or assistive technologies.
              Skip links use a function that’s built in to your browser.
              All that is required for a skip link is an anchor that points to an id on the page (like <code>&lt;a href="#main"&gt;</code>) and an element with that id (like <code>&lt;main id="main"&gt;</code>).
              Activating the anchor will move focus to the target element.
            </p>
            
            <p>
              The big benefit is that your next press of the <kbd>Tab</kbd> key will set focus to the first focusable element
              (such as a link, button, or form field) within the target element.
              You’ve skipped over the repetitive focusable elements earlier in the page (such as those navigation links), hence the name.
            </p>
        </section>
        
        <section id="sticky-headers" aria-labelledby="sticky-headers-heading" tabindex="-1">
            <h2 id="sticky-headers-heading">How to make skip links work with sticky headers</h2>
            
            <p>
              A common issue with this technique is that,
              by default,
              the target element is scrolled to the top of the <a href="https://developer.mozilla.org/en-US/docs/Glossary/Viewport">viewport</a> when the skip link is activated.
              This is an issue if the page has a fixed element—such as a sticky header—that obscures the top of the viewport.
              Luckily, there’s a CSS property to fix this: <a href="https://drafts.csswg.org/css-scroll-snap-1/#propdef-scroll-padding"><code>scroll-padding</code></a>!
            </p>
            
            <p>
              <code>scroll-padding</code> specifies offsets that lets you tell the browser which parts of your page are obscured by things like UI elements (such as a sticky header).
              Like <code>padding</code> and <code>margin</code>, <code>scroll-padding</code> is a shorthand property.
              This means that you can also use the longhand version to define specific sides, like so: <code>scroll-padding-top: 2em;</code>.
            </p>
            
            <p>
              To use <code>scroll-padding</code>,
              we’ll need to know how much space we need to bridge.
              The sticky header on this page is <code>5rem</code> high.
              To get the browser to skip this part when it calculates where to scroll the page to,
              we use <code>scroll-padding-top: 5rem;</code>.
            </p>
            
            <aside class="note">
              <p>
                Note: you’re free to use other units.
                This page was built with <code>em</code> and <code>rem</code>,
                which is why those units are also used in the <code>scroll-padding</code> declaration.
              </p>
            </aside>
            
            <p>
              The padding specified by <code>scroll-padding</code> will be applied to the ‘<a href="https://drafts.csswg.org/css-overflow-3/#scroll-container">scroll container</a>’ that it’s added to.
              My understanding of this part of the specification is a bit fuzzy (feel free to explain it to me).
              But it seems like this would be the <code>&lt;html&gt;</code> element for skip links as described and used in this article.
            </p>
            
            <section id="the-code">
                <h3>The Code</h3>

                <p>Our CSS would end up looking something like this:</p>

<pre><code>html {
    scroll-padding-top: 5em;
}</code></pre>

                <p>HTML:</p>

<pre><code>&lt;html&gt;
    &lt;header&gt;
        &lt;a href="#main-content"&gt;Skip to main content&lt;/a&gt;
    &lt;/header&gt;
    &lt;main id="main-content" tabindex="-1"&gt;
        &lt;h1&gt;Fancy title for your content&lt;/h1&gt;
    &lt;/main&gt;
&lt;/html&gt; </code></pre>

                <aside class="note">
                    <p>
                      Note: the <code>tabindex="-1"</code> on the main content element isn’t needed to make skip links work.
                      It is, however, needed to get the animated focus state.
                    </p>
                </aside>
            </section>

            <section>
                <h3>The Result</h3>

                <p>
                  If we did everything right,
                  our heading (or other content) should no longer be chopped in half when we activate a skip link!
                </p>

                <figure>
                    <img src="https://assets.codepen.io/154571/after.png" alt="">
                    <figcaption>
                      What we wanted to achieve:
                      the newly focused content is visible in full;
                      no more overlapping from the sticky header.
                    </figcaption>
                </figure>
            </section>
        </section>
        
        <section id="support" aria-labelledby="support-heading" tabindex="-1">
            <h2 id="support-heading">Browser Support</h2>
            <p>Seems to work everywhere except for Internet Explorer 11.</p>
            
            <section>
              <h3>Couldn’t browsers calculate this for us?</h3>
            
              <p>The short answer is “probably not”—though wouldn’t that be a great feature to have?</p>
              
              <p>
                The CSS Scroll Snap specification—which <code>scroll-padding</code> is defined in—mentions an <code>auto</code> value that might at first seem helpful,
                but it turns out that <code>auto</code> is merely <code>scroll-padding</code>’s default value:
              </p>

              <blockquote>
                  <p>
                    [<code>auto</code>] indicates that the offset for the corresponding edge of the scrollport is UA-determined.
                    This should generally default to a used length of <code>0px</code>,
                    but UAs may use heuristics to detect when a non-zero value is more appropriate.
                  </p>
              </blockquote>
              
              <p>
                The wording here means that while browsers are allowed to calculate <code>scroll-padding</code> values other than <code>0px</code>,
                it means they almost certainly won’t.
              </p>
              
              <p>
                With that in mind,
                your best bet is to specify <code>scroll-padding</code> values yourself.
                Who knows what the future might hold, though.
              </p>
        </section>
        
        <section id="resources" aria-labelledby="resources-heading" tabindex="-1">
            <h2 id="resources-heading">Related resources</h2>
            <ul>
                <li>
                    <a href="https://drafts.csswg.org/css-scroll-snap-1/#propdef-scroll-padding">CSS Scroll Snap Module Level 1</a>
                </li>
                <li>
                    <a href="https://developer.mozilla.org/en-US/docs/Web/CSS/scroll-padding">MDN article on ‘scroll-padding’</a>
                </li>
                <li>
                  <a href="https://www.w3.org/TR/WCAG21/#bypass-blocks">WCAG: §2.4.1 Bypass Blocks</a>
                </li>
            </ul>
        </section>
    </main>
</div>
<footer>
    <p>Words by <a href="../">Zoë Bijl</a>. Edited by <a href="https://www.friendlyediting.com/">Ashley Bischoff</a></p>
</footer>
!

CSS 

              
                html {
	scroll-padding-top: 5rem; /* the star of this article! */
	/* enable the line below to see what happens without the scroll-padding! */
	/*scroll-padding-top: 0;*/
}

body {
	margin: 0; /* reset the body’s default margin  */
}

body > header {
	position: fixed; /* this is how we make our header sticky */
}

div.layout {
	padding-top: 5rem; /* this is how the visual offset created by the sticky header is usually fixed */
}

/* This provides the nice thicc border the main element gets on focus */
main:focus {
	animation: 3s linear 1 running main-focus;
}

@keyframes main-focus {
	0% {
		box-shadow: inset 0 0 0 1em var(--content-focus-full);
	}
	
	100% {
		box-shadow: inset 0 0 0 1em var(--content-focus-null);
	}
}

/* Same thing for the sections but with background colours */
section:focus {
	outline: 1em transparent;
	animation: 1.5s linear 1 running section-focus;
}

@keyframes section-focus {
	0% {
		background: var(--content-focus-full);
	}
	
	100% {
		background: var(--content-focus-null);
	}
}

/* transparent focus outline visible in High Contrast Modes */
main:focus,
section:focus {
	outline: transparent solid 1em;
	outline-offset: -1em;
}

/* Styles not necessarily related to the technique */
* {
	box-sizing: border-box;
}

html {
	color: var(--body-text);
	background: var(--body-background);
}

body {
	font-family: sans-serif;
	line-height: 1.5;
}

main,
footer {
	margin: 0 auto;
	padding: 1em;
	max-width: var(--page-max-width);
}

div.clamp {
	margin-right: auto;
	margin-left: auto;
	padding-right: 1em;
	padding-left: 1em;
	max-width: var(--page-max-width);
}

body > header {
	top: 0;
	right: 0;
	left: 0;
	z-index: 2;
	padding-top: .5rem;
	background: var(--body-background);
}

body > header a {
	color: inherit;
}

nav {
	margin: .5rem -1rem 0;
	padding: .5rem 1rem;
	color: white;
	text-align: right;
	background: var(--header-background);
}

nav a + a {
	margin-left: 1em;
}

aside.note {
	padding: .25em;
	padding-left: 1em;
	border-left: .5em solid;
}

aside.note,
figure.note {
	border-left-color: #e0cb52;
	background: rgba(255, 255, 255, .05);
}

a {
	color: var(--link-text);
}

h1 {
	margin-top: 0;
}

h2,
h3 {
	margin-top: 2rem;
}

pre {
	max-width: 100%;
	overflow-x: auto;
}

code,
kbd {
	display: inline-block;
	padding: .125em .25em;
	border: .0675em solid var(--code-border);
	border-radius: .25em;
	color: var(--code-text);
	font-family: "Courier", monospace;
	font-size: .9em;
	font-weight: 700;
	line-height: 1.25;
	background: var(--code-background);
}

kbd {
	color: var(--kbd-text);
}

a code {
	padding: inherit;
	border: none;
	color: inherit;
	line-height: inherit;
	text-decoration: underline;
	vertical-align: text-bottom;
	background: inherit;
}

img {
	max-width: 100%;
}

figure {
	margin: 1em 0;
	padding: 1em;
	border-left: .5em solid var(--figure-border);
	background: var(--figure-background);
}

figure > img {
	padding: .125em .25em;
	border: .0675em solid var(--figure-img-border);
	border-radius: .25em;
}

figcaption {
	margin-top: .5em;
	font-style: italic;
}

@media (min-width: 40em) {
	main header {
		display: flex;
		align-items: baseline;
		justify-content: space-between;
	}
	main header time {
		position: relative;
		margin-top: 0;
		padding-left: 1.6em;
		text-align: right;
	}
	main header time span {
		clip: rect(0 0 0 0);
		position: absolute;
		overflow: hidden;
		width: 1px;
		white-space: nowrap;
	}
}

/* Colour Definitions */
:root {
	--page-max-width: 41em;
	--body-text: black;
	--body-background: white;
	--link-text: royalblue;
	--header-background: purple;
	--content-focus-full: rgba(128, 0, 128, .5);
	--content-focus-null: rgba(128, 0, 128, 0);
	--code-border: #666;
	--code-text: rebeccapurple;
	--code-background: whitesmoke;
	--kbd-text: #ff2c6d;
	--figure-border: var(--content-focus-full);
	--figure-background: rgba(128, 0, 128, .2);
	--figure-img-border: #666;
}

/* Dark Mode */
@media (prefers-color-scheme: dark) {
	:root {
		--body-text: white;
		--body-background: hsl(260, 15%, 16%);
		--link-text: #7DC2FF;
		--header-background: hsl(268, 22%, 46%);
		--content-focus-full: hsla(262, 16%, 57%, .7);
		--content-focus-null: hsla(262, 16%, 57%, 0);
		--code-border: #000;
		--code-text: hsl(270, 59%, 74%);
		--code-background: #191A19;
		--kbd-text: hotpink;
		--figure-border: var(--content-focus-full);
		--figure-background: hsl(260, 16%, 23%);
		--figure-img-border: hsl(263, 17%, 69%);
	}
}
!

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