:root {
	--bg: #f7f9fc;
	--surface: #ffffff;
	--text: #18212f;
	--muted: #516079;
	--primary: #306cff;
	--primary-dark: #1f53d1;
	--border: #dce3ef;
	--footer: #0f172a;
}

* {
	box-sizing: border-box;
}

html,
body {
	margin: 0;
	padding: 0;
}

body {
	font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
	line-height: 1.6;
	color: var(--text);
	background: var(--bg);
}

img {
	display: block;
	max-width: 100%;
	height: auto;
}

a {
	color: inherit;
	text-decoration: none;
}

.container {
	width: min(100% - 2rem, 1100px);
	margin-inline: auto;
}

.section {
	padding: 3.5rem 0;
}

.section-title {
	margin: 0 0 1.25rem;
	font-size: clamp(1.5rem, 2.6vw, 2rem);
	line-height: 1.2;
}

.site-header {
	position: sticky;
	top: 0;
	z-index: 1000;
	background: rgba(255, 255, 255, 0.95);
	backdrop-filter: blur(8px);
	border-bottom: 1px solid var(--border);
}

.header-inner {
	display: flex;
	align-items: center;
	justify-content: space-between;
	padding: 0.9rem 0;
	position: relative;
}

.logo {
	font-weight: 800;
	letter-spacing: 0.2px;
	color: #0d1b3d;
}

.nav-toggle {
	position: absolute;
	opacity: 0;
	pointer-events: none;
}

.hamburger {
	width: 2.2rem;
	height: 2.2rem;
	display: inline-flex;
	flex-direction: column;
	justify-content: center;
	gap: 0.28rem;
	cursor: pointer;
}

.hamburger span {
	height: 2px;
	width: 100%;
	background: var(--text);
	border-radius: 999px;
}

.site-nav {
	position: absolute;
	left: 0;
	right: 0;
	top: 100%;
	background: var(--surface);
	border-bottom: 1px solid var(--border);
	max-height: 0;
	overflow: hidden;
	transition: max-height 0.3s ease;
}

.site-nav ul {
	list-style: none;
	margin: 0;
	padding: 0.6rem 1rem 1rem;
	display: grid;
	gap: 0.4rem;
}

.site-nav a {
	display: block;
	padding: 0.55rem 0.65rem;
	border-radius: 0.5rem;
	color: var(--text);
	font-weight: 600;
}

.site-nav a:hover,
.site-nav a:focus-visible {
	background: #eef3ff;
	color: #12316f;
}

.nav-toggle:checked ~ .site-nav {
	max-height: 16rem;
}

.hero {
	background: linear-gradient(135deg, #102247 0%, #1d3e7b 55%, #306cff 100%);
	color: #fff;
	padding: 5rem 0 4.25rem;
}

.hero-content {
	max-width: 700px;
}

.eyebrow {
	margin: 0;
	text-transform: uppercase;
	letter-spacing: 0.08em;
	font-weight: 700;
	color: #c4d8ff;
	font-size: 0.82rem;
}

.hero h1 {
	margin: 0.7rem 0 1rem;
	font-size: clamp(2rem, 7vw, 3.3rem);
	line-height: 1.12;
}

.hero p {
	margin: 0;
	max-width: 60ch;
	color: #e9eeff;
}

.btn {
	margin-top: 1.4rem;
	display: inline-block;
	background: #fff;
	color: #163674;
	font-weight: 700;
	padding: 0.78rem 1.2rem;
	border-radius: 0.7rem;
}

.btn:hover,
.btn:focus-visible {
	background: #eaf0ff;
}

.features {
	background: #f6f8ff;
}

.feature-grid {
	display: grid;
	gap: 1rem;
}

.card {
	background: var(--surface);
	border: 1px solid var(--border);
	border-radius: 0.9rem;
	padding: 1.2rem;
}

.card h3 {
	margin-top: 0;
	margin-bottom: 0.5rem;
	font-size: 1.12rem;
}

.card p {
	margin: 0;
	color: var(--muted);
}

.course-code {
	font-size: 0.9rem;
	font-weight: 600;
	color: #1d4ed8;
	margin-bottom: 0.8rem !important;
}

.task-list {
	list-style: none;
	margin: 0;
	padding: 0;
	display: grid;
	gap: 0.5rem;
}

.task-list li {
	font-size: 0.9rem;
	color: var(--muted);
	padding-left: 0;
	position: relative;
	display: flex;
	align-items: flex-start;
	gap: 0.5rem;
}

.task-list input[type="checkbox"] {
	width: 1.1rem;
	height: 1.1rem;
	min-width: 1.1rem;
	margin-top: 0.15rem;
	cursor: pointer;
	accent-color: var(--primary);
}

.task-list label {
	cursor: pointer;
	flex: 1;
}

.task-list input[type="checkbox"]:checked + label {
	color: #999;
	text-decoration: line-through;
}

.about-layout {
	display: grid;
	gap: 1.4rem;
}

.about-image-wrapper img {
	border-radius: 1rem;
	width: 100%;
	object-fit: cover;
}

.about-copy p {
	margin: 0 0 0.8rem;
	color: var(--muted);
}

.site-footer {
	background: var(--footer);
	color: #e5ebff;
	margin-top: 2rem;
}

.footer-layout {
	padding: 2.2rem 0 1.3rem;
	display: grid;
	gap: 1.3rem;
}

.site-footer h3,
.site-footer h4 {
	margin: 0 0 0.5rem;
	color: #fff;
}

.site-footer p {
	margin: 0;
	color: #b8c2de;
}

.footer-links,
.social-links {
	list-style: none;
	margin: 0;
	padding: 0;
	display: grid;
	gap: 0.4rem;
}

.social-links {
	display: flex;
	align-items: center;
	gap: 0.6rem;
}

.social-links a {
	display: inline-flex;
	align-items: center;
	justify-content: center;
	width: 2.2rem;
	height: 2.2rem;
	border: 1px solid #2a375b;
	border-radius: 999px;
	transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
}

.social-links svg {
	width: 1rem;
	height: 1rem;
	fill: currentColor;
}

.footer-links a,
.social-links a {
	color: #d6deff;
}

.footer-links a:hover,
.social-links a:hover,
.footer-links a:focus-visible,
.social-links a:focus-visible {
	color: #fff;
}

.social-links a:hover,
.social-links a:focus-visible {
	background: #1f2a47;
	border-color: #43547f;
}

.sr-only {
	position: absolute;
	width: 1px;
	height: 1px;
	padding: 0;
	margin: -1px;
	overflow: hidden;
	clip: rect(0, 0, 0, 0);
	white-space: nowrap;
	border: 0;
}

.copyright {
	text-align: center;
	border-top: 1px solid #2a375b;
	padding: 0.95rem 1rem 1.2rem;
	color: #b7c2de;
	font-size: 0.92rem;
}

@media (min-width: 768px) {
	.feature-grid {
		grid-template-columns: repeat(2, minmax(0, 1fr));
	}

	.about-layout {
		grid-template-columns: 1fr 1fr;
		align-items: center;
	}

	.footer-layout {
		grid-template-columns: repeat(3, minmax(0, 1fr));
	}
}

@media (min-width: 1024px) {
	.hamburger {
		display: none;
	}

	.site-nav {
		position: static;
		max-height: none;
		overflow: visible;
		border: 0;
		background: transparent;
	}

	.site-nav ul {
		padding: 0;
		display: flex;
		align-items: center;
		gap: 0.5rem;
	}

	.site-nav a {
		padding-inline: 0.85rem;
	}

	.feature-grid {
		grid-template-columns: repeat(4, minmax(0, 1fr));
	}

	.hero {
		padding: 6rem 0 5rem;
	}

	.about-layout {
		grid-template-columns: 1.1fr 1fr;
		gap: 2rem;
	}
}