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HTML 

              
                <div class="nav">
	<a href="#">
		<h1>STEM Initiative</h1>
	</a>
	<ul>

	</ul>
	<button id="darkmode">
		<svg class="moon" stroke="currentColor" stroke-linecap="round" stroke-linejoin="round" stroke-width="2" width="24" height="24" viewBox="0 0 24 24">
			<defs></defs>
			<path d="M21 12.79A9 9 0 1111.21 3 7 7 0 0021 12.79z"></path>
		</svg>
	</button>
</div>
<main>
	<section>
		<h1 class="page-title">STEM Initiative's Leadership</h1>
	</section>
	<div class="leadership">
		<div class="leader">
			<div class="leader__header">
				<div class="leader__exp">
					<span class="years">8</span>
					<span>years with STEM Initiative</span>
				</div>
				<a href="#" class="leader__bio">Bio</a>
			</div>
			<div class="leader__img">
				<img src="https://images.unsplash.com/photo-1494790108377-be9c29b29330?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=987&q=80" alt="Amanda Maynard">
			</div>
			<div class="leader__name">
				<h2>Amanda Maynard</h2>
				<p><em>President, STEM</em></p>
			</div>
		</div>

		<div class="leader">
			<div class="leader__header">
				<div class="leader__exp">
					<span class="years">6</span>
					<span>years with STEM Initiative</span>
				</div>
				<a href="#" class="leader__bio">Bio</a>
			</div>
			<div class="leader__img">
				<img src="https://images.unsplash.com/photo-1611432579402-7037e3e2c1e4?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=1365&q=80" alt="Sammy Cotillard">
			</div>
			<div class="leader__name">
				<h2>Sammy Cotillard</h2>
				<p><em>Vice President, STEM</em></p>
			</div>
		</div>

		<div class="leader">
			<div class="leader__header">
				<div class="leader__exp">
					<span class="years">5</span>
					<span>years with STEM Initiative</span>
				</div>
				<a href="#" class="leader__bio">Bio</a>
			</div>
			<div class="leader__img">
				<img src="https://images.unsplash.com/photo-1560250097-0b93528c311a?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=987&q=80" alt="Todd Fletcher">
			</div>
			<div class="leader__name">
				<h2>Todd Fletcher</h2>
				<p><em>Chief Financial Officer</em></p>
			</div>
		</div>

		<div class="leader">
			<div class="leader__header">
				<div class="leader__exp">
					<span class="years">4</span>
					<span>years with STEM Initiative</span>
				</div>
				<a href="#" class="leader__bio">Bio</a>
			</div>
			<div class="leader__img">
				<img src="https://images.unsplash.com/photo-1601931935821-5fbe71157695?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=927&q=80" alt="Tiffany Edwards">
			</div>
			<div class="leader__name">
				<h2>Tiffany Edwards</h2>
				<p><em>Director of Marketing</em></p>
			</div>
		</div>

		<div class="leader">
			<div class="leader__header">
				<div class="leader__exp">
					<span class="years">3</span>
					<span>years with STEM Initiative</span>
				</div>
				<a href="#" class="leader__bio">Bio</a>
			</div>
			<div class="leader__img">
				<img src="https://images.unsplash.com/photo-1573496359142-b8d87734a5a2?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=988&q=80" alt="Chelsea Clayton">
			</div>
			<div class="leader__name">
				<h2>Chelsea Clayton</h2>
				<p><em>Director of Public Relations</em></p>
			</div>
		</div>

		<div class="leader">
			<div class="leader__header">
				<div class="leader__exp">
					<span class="years">2</span>
					<span>years with STEM Initiative</span>
				</div>
				<a href="#" class="leader__bio">Bio</a>
			</div>
			<div class="leader__img">
				<img src="https://images.unsplash.com/photo-1531427186611-ecfd6d936c79?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=987&q=80" alt="Kevin McCallister">
			</div>
			<div class="leader__name">
				<h2>Kevin McCallister</h2>
				<p><em>Art Director</em></p>
			</div>
		</div>
	</div>

</main>
!

CSS 

              
                :root {
	--background: #f5f6fa;
	--page-title: #3b3b98;
	--btn: #dcdde1;
	--btn-text: #b33771;
	--btn-text-hover: #dcdde1;
	--btn-bkg: #b33771;
	--btn-fill: transparent;
	--nav-bkg: rgba(245, 246, 250, 0.75);
	--nav-logo: #b33771;
	--nav-border: rgba(245, 246, 250, 0.2);
	--header-bkg: #3b3b98;
	--bio-text: #fff;
	--bio-bkg: #182c61;
	--bio-bkg-hover: #b33771;
	--name-text: #2c3a47;
	--name-text-hover: #3b3b98;
}

.dark:root {
	--background: #182c61;
	--page-title: #fff;
	--btn-text: #dcdde1;
	--btn-text-hover: #dcdde1;
	--btn-bkg: #273c75;
	--btn-fill: #dcdde1;
	--nav-bkg: rgba(24, 44, 97, 0.75);
	--nav-logo: #fff;
	--nav-border: rgba(24, 44, 97, 0.2);
	--header-bkg: #6d214f;
	--bio-text: #fff;
	--bio-bkg: #b33771;
	--bio-bkg-hover: #3b3b98;
	--name-text-hover: #b33771;
}

* {
	box-sizing: border-box;
	margin: 0;
	padding: 0;
}

html {
	font-size: 10px;
}

body {
	background: var(--background);
	display: flex;
	flex-direction: column;
	align-items: center;
}

button {
	border: 0;
	background: none;
	fill: var(--btn-fill);
	color: var(--btn-text);
	line-height: 0;
	padding: 0.8rem;
	border-radius: 2rem;
	display: flex;
	justify-content: center;
	align-items: center;
	transition: 0.2s ease;

	&:hover {
		cursor: pointer;
		background: var(--btn-bkg);
		fill: var(--btn-fill);
		color: var(--btn-text-hover);
	}
}

main {
	max-width: 1200px;
	margin: 0 auto;
	padding: 2rem;
	position: absolute;
	top: 130px;
}

.nav {
	position: fixed;
	z-index: 999;
	display: flex;
	padding: 0.25rem 2rem;
	width: 100%;
	justify-content: space-between;
	align-items: center;
	background: var(--nav-bkg);
	box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.2);
	backdrop-filter: blur(6px);
	-webkit-backdrop-filter: blur(4px);
	border: 1px solid var(--nav-border);

	a {
		text-decoration: none;
		color: var(--nav-logo);
		h1 {
			font-size: 3rem;
			font-weight: 300;
			letter-spacing: 1px;
		}
	}
}

.page-title {
	color: var(--page-title);
	font-size: 4rem;
	margin-bottom: 5rem;
	margin-top: 0;
}

.leadership {
	display: grid;
	// grid-template-rows: repeat(2, 1fr);
	grid-template-columns: 1fr;
	gap: 2rem;

	@media (min-width: 32em) {
		grid-template-columns: repeat(2, 1fr);
	}

	@media (min-width: 50em) {
		grid-template-columns: repeat(3, 1fr);
	}

	.leader {
		width: 100%;
		box-shadow: 0 3px 20px rgba(0, 0, 0, 0.5);

		@media (min-width: 32em) {
			max-width: 300px;
		}

		&:hover {
			cursor: pointer;

			.leader__bio {
				background-color: var(--bio-bkg-hover);
			}
			.leader__img img {
				transform: scale(140%);
				filter: saturate(100%);
			}
			.leader__name {
				color: var(--name-text-hover);
			}
		}

		&__header {
			display: flex;
			justify-content: space-between;
			align-items: center;
			height: 80px;
			background: var(--header-bkg);
			color: #fff;
		}
		&__exp {
			display: flex;
			align-items: center;
			font-size: 1.5rem;
			padding: 1rem 2rem;
			.years {
				font-size: 5rem;
				margin-right: 8px;
				font-weight: 700;
			}
		}
		&__bio {
			padding: 1.5rem 2rem;
			font-size: 2.5rem;
			text-decoration: none;
			color: var(--bio-text);
			height: 100%;
			display: flex;
			flex-direction: column;
			justify-content: center;
			text-align: center;
			background: var(--bio-bkg);
			transition: 0.2s all ease-in-out;
		}
		&__img {
			overflow: hidden;
			width: 100%;
			height: 300px;
			position: relative;
			img {
				position: absolute;
				margin: auto;
				left: 0;
				right: 0;
				text-align: center;
				width: 100%;
				filter: saturate(0%);
				transform: scale(130%);
				transition: 0.2s all ease-in-out;
			}
		}
		&__name {
			text-align: center;
			padding: 1.5rem;
			font-size: 2rem;
			background: #fff;
			display: flex;
			flex-direction: column;
			justify-content: center;
			transition: 0.2s all ease-in-out;
			color: var(--name-text);

			@media (min-width: 32em) {
				font-size: 1.5rem;
			}
			@media (min-width: 50em) {
				font-size: 2rem;
			}

			h2 {
				font-size: 2.5rem;

				@media (min-width: 32em) {
					font-size: 2rem;
				}
				@media (min-width: 50em) {
					font-size: 2.5rem;
				}
			}
		}
	}
}
!

JS 

              
                const modeSwitch = document.querySelector("#darkmode");

modeSwitch.addEventListener("click", function () {
	document.documentElement.classList.toggle("dark");
});
!
999px

Console