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HTML

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CSS

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CSS Base

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JavaScript

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Babel includes JSX processing.

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HTML 

              
                <ul>
	<div class="bar"></div>
	<li><div class="icon"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path fill="none" d="M0 0h24v24H0V0z"/><path d="M12 5.69l5 4.5V18h-2v-6H9v6H7v-7.81l5-4.5M12 3L2 12h3v8h6v-6h2v6h6v-8h3L12 3z"/></svg></div><div class="text">Home</div></li>
	<li><div class="icon"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path fill="none" d="M0 0h24v24H0V0z"/><path d="M14 2H6c-1.1 0-1.99.9-1.99 2L4 20c0 1.1.89 2 1.99 2H18c1.1 0 2-.9 2-2V8l-6-6zM6 20V4h7v5h5v11H6z"/></svg></div><div class="text">Files</div></li>
	<li><div class="icon"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path fill="none" d="M0 0h24v24H0V0z"/><path d="M12 6c1.1 0 2 .9 2 2s-.9 2-2 2-2-.9-2-2 .9-2 2-2m0 10c2.7 0 5.8 1.29 6 2H6c.23-.72 3.31-2 6-2m0-12C9.79 4 8 5.79 8 8s1.79 4 4 4 4-1.79 4-4-1.79-4-4-4zm0 10c-2.67 0-8 1.34-8 4v2h16v-2c0-2.66-5.33-4-8-4z"/></svg></div><div class="text">Profile</div></li>
	<li><div class="icon"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path fill="none" d="M0 0h24v24H0V0z"/><path d="M11.99 18.54l-7.37-5.73L3 14.07l9 7 9-7-1.63-1.27zM12 16l7.36-5.73L21 9l-9-7-9 7 1.63 1.27L12 16zm0-11.47L17.74 9 12 13.47 6.26 9 12 4.53z"/></svg></div><div class="text">Layers</div></li>
	<li><div class="icon"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path fill="none" d="M0 0h24v24H0V0z"/><path d="M19.43 12.98c.04-.32.07-.64.07-.98 0-.34-.03-.66-.07-.98l2.11-1.65c.19-.15.24-.42.12-.64l-2-3.46c-.09-.16-.26-.25-.44-.25-.06 0-.12.01-.17.03l-2.49 1c-.52-.4-1.08-.73-1.69-.98l-.38-2.65C14.46 2.18 14.25 2 14 2h-4c-.25 0-.46.18-.49.42l-.38 2.65c-.61.25-1.17.59-1.69.98l-2.49-1c-.06-.02-.12-.03-.18-.03-.17 0-.34.09-.43.25l-2 3.46c-.13.22-.07.49.12.64l2.11 1.65c-.04.32-.07.65-.07.98 0 .33.03.66.07.98l-2.11 1.65c-.19.15-.24.42-.12.64l2 3.46c.09.16.26.25.44.25.06 0 .12-.01.17-.03l2.49-1c.52.4 1.08.73 1.69.98l.38 2.65c.03.24.24.42.49.42h4c.25 0 .46-.18.49-.42l.38-2.65c.61-.25 1.17-.59 1.69-.98l2.49 1c.06.02.12.03.18.03.17 0 .34-.09.43-.25l2-3.46c.12-.22.07-.49-.12-.64l-2.11-1.65zm-1.98-1.71c.04.31.05.52.05.73 0 .21-.02.43-.05.73l-.14 1.13.89.7 1.08.84-.7 1.21-1.27-.51-1.04-.42-.9.68c-.43.32-.84.56-1.25.73l-1.06.43-.16 1.13-.2 1.35h-1.4l-.19-1.35-.16-1.13-1.06-.43c-.43-.18-.83-.41-1.23-.71l-.91-.7-1.06.43-1.27.51-.7-1.21 1.08-.84.89-.7-.14-1.13c-.03-.31-.05-.54-.05-.74s.02-.43.05-.73l.14-1.13-.89-.7-1.08-.84.7-1.21 1.27.51 1.04.42.9-.68c.43-.32.84-.56 1.25-.73l1.06-.43.16-1.13.2-1.35h1.39l.19 1.35.16 1.13 1.06.43c.43.18.83.41 1.23.71l.91.7 1.06-.43 1.27-.51.7 1.21-1.07.85-.89.7.14 1.13zM12 8c-2.21 0-4 1.79-4 4s1.79 4 4 4 4-1.79 4-4-1.79-4-4-4zm0 6c-1.1 0-2-.9-2-2s.9-2 2-2 2 .9 2 2-.9 2-2 2z"/></svg></div><div class="text">Settings</div></li>
</ul>
!

CSS 

              
                html, body
{
	--color: #FAC300;
	--icon-width: 60px;
	--text-width: 90px;
	--padding: 2.5rem;
	--duration: 0.2s;

	font-family: sans-serif;
	background-color: var(--color);
	height: 100%;
	margin: 0;
	padding: 0;
	display: flex;
	align-items: center;
	justify-content: center;
}

.bar
{
	width: calc(var(--icon-width) + var(--text-width));
	height: calc(100% - var(--padding));
	background-color: var(--color);
	position: absolute;
	top: calc(var(--padding) * 0.5);
	left: calc(var(--padding) * 0.5);
	border-radius: var(--icon-width);
	transform: translatex(calc(var(--icon-width) * var(--active)));
	transition: transform var(--duration) ease-in-out;
}

ul
{
	list-style: none;
	background-color: white;
	margin: 0;
	padding: var(--padding) calc(var(--padding) / 2);
	position: relative;
	padding-right: calc(var(--text-width) + var(--padding) / 2);
	box-shadow: 0px 0px 15px rgba(0, 0, 0, 0.2);
	display: grid;
	grid-auto-flow: column;
}

li
{
	position: relative;
	
	>*
	{
		display: flex;
		justify-content: flex-start;
		align-items: center;
		height: 0;
	}
	
	.icon
	{ 
		z-index: 100;
		justify-content: center;
		width: var(--icon-width);
		cursor: pointer;
		text-align: center;
		opacity: 0.3;
		transition-property: opacity, transform;
		transition-duration: var(--duration);
		transition-timing-function: ease-in-out;
	}
	
	.text
	{
		position: absolute;
		left: 0;
		top: 0;
		opacity: 0;
		width: var(--text-width);
		margin-left: var(--icon-width);
		pointer-events: none;
		transition: opacity var(--duration) ease-in-out;
		height: 100%;
		font-size: 0.9rem;
		font-weight: bold;
	}
	
	&[data-active]
	{
		.text, .icon { opacity: 1 }
	}
}

[data-active] ~ li .icon
{
	transform: translatex(calc((var(--i) * 1px) + var(--text-width)));
}
!

JS 

              
                const root = document.documentElement;
const items = Array.from(document.querySelectorAll("li"));
root.style.setProperty('--active', 0);

items.forEach((item, index) => 
{
	if(index === 0) item.setAttribute("data-active", true);
	item.style.setProperty('--i', index);
	
  	item.addEventListener("click", e => 
	{
		root.style.setProperty('--active', index);
		root.querySelectorAll("[data-active]").forEach(el => el.removeAttribute("data-active"));
    	item.setAttribute("data-active", true);
  	});
});
!
999px

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