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

:root {
	--ink: #111210;
	--paper: #F8F7F3;
	--muted: #6B6A63;
	--border: #E0DED6;
	--accent: #1A6B45;
	--accent-light: #EBF4EE;
	--lecture: #6A4C93;
	--lecture-bg: #F2ECFB;
	--serif: 'Instrument Serif', Georgia, serif;
	--sans: 'DM Sans', sans-serif;
}

body {
	font-family: var(--sans);
	background: var(--paper);
	color: var(--ink);
	min-height: 100vh;
}

nav {
	display: flex;
	align-items: center;
	justify-content: space-between;
	gap: 24px;
	padding: 18px 48px;
	border-bottom: 1px solid var(--border);
	background: var(--paper);
	position: sticky;
	top: 0;
	z-index: 100;
}

.brand-block {
	display: flex;
	flex-direction: column;
	align-items: flex-start;
	gap: 2px;
}

.logo {
	font-family: var(--serif);
	font-size: 22px;
	color: var(--ink);
	letter-spacing: -0.3px;
}

.logo span { color: var(--accent); }

.tagline {
	font-size: 11px;
	color: var(--muted);
	font-weight: 500;
}

.nav-links {
	display: flex;
	gap: 32px;
	list-style: none;
}

.nav-links a {
	text-decoration: none;
	color: var(--muted);
	font-size: 14px;
	font-weight: 400;
	transition: color .2s;
}

.nav-links a:hover { color: var(--ink); }

.nav-cta {
	background: var(--accent);
	color: var(--paper);
	padding: 9px 20px;
	border-radius: 6px;
	font-size: 14px;
	font-weight: 500;
	text-decoration: none;
	transition: opacity .2s;
}

.nav-cta:hover { opacity: .85; }

main {
	max-width: 960px;
	margin: 0 auto;
	padding: 56px 24px 80px;
}

.page-header {
	margin-bottom: 24px;
}

.exam-badge {
	display: inline-block;
	font-size: 11px;
	font-weight: 500;
	letter-spacing: 1px;
	text-transform: uppercase;
	color: var(--accent);
	background: var(--accent-light);
	padding: 5px 12px;
	border-radius: 20px;
	margin-bottom: 16px;
}

.page-header h1 {
	font-family: var(--serif);
	font-size: clamp(28px, 4vw, 40px);
	font-weight: 400;
	line-height: 1.15;
	letter-spacing: -0.5px;
	margin-bottom: 10px;
}

.page-header h1 em {
	color: var(--accent);
	font-style: italic;
}

.page-header p {
	font-size: 15px;
	color: var(--muted);
}

.lecture-grid {
	display: grid;
	grid-template-columns: repeat(2, minmax(0, 1fr));
	gap: 16px;
	margin-bottom: 22px;
}

.lecture-card {
	display: flex;
	gap: 14px;
	background: #fff;
	border: 1px solid var(--border);
	border-radius: 14px;
	padding: 20px;
	transition: border-color .2s, box-shadow .2s, transform .2s;
}

.lecture-card:hover {
	border-color: var(--lecture);
	box-shadow: 0 8px 24px rgba(0, 0, 0, 0.06);
	transform: translateY(-2px);
}

.lecture-card.active {
	border-color: var(--lecture);
	box-shadow: 0 0 0 1px rgba(106, 76, 147, 0.25);
}

.lecture-icon {
	width: 44px;
	height: 44px;
	border-radius: 10px;
	background: var(--lecture-bg);
	color: var(--lecture);
	display: flex;
	align-items: center;
	justify-content: center;
	flex-shrink: 0;
}

.lecture-icon svg {
	width: 22px;
	height: 22px;
}

.lecture-body {
	flex: 1;
}

.lecture-body h2 {
	font-family: var(--serif);
	font-size: 23px;
	font-weight: 400;
	margin-bottom: 6px;
}

.lecture-body p {
	font-size: 13px;
	line-height: 1.6;
	color: var(--muted);
	margin-bottom: 14px;
}

.lecture-actions {
	display: flex;
	align-items: center;
	gap: 10px;
	flex-wrap: wrap;
}

.play-btn {
	border: 0;
	border-radius: 8px;
	padding: 10px 14px;
	font-family: var(--sans);
	font-size: 13px;
	font-weight: 600;
	cursor: pointer;
	background: var(--accent);
	color: #fff;
	transition: background .2s, transform .2s;
}

.play-btn:hover {
	background: #155c39;
	transform: translateY(-1px);
}

.youtube-link {
	color: var(--muted);
	text-decoration: none;
	font-size: 13px;
	font-weight: 500;
}

.youtube-link:hover {
	color: var(--ink);
	text-decoration: underline;
}

.player-wrap {
	background: #fff;
	border: 1px solid var(--border);
	border-radius: 14px;
	padding: 18px;
}

.player-head {
	margin-bottom: 12px;
}

.player-head h3 {
	font-family: var(--serif);
	font-size: 26px;
	font-weight: 400;
	margin-bottom: 4px;
}

.player-head p {
	font-size: 13px;
	color: var(--muted);
}

.player-frame {
	width: 100%;
	aspect-ratio: 16 / 9;
	border-radius: 10px;
	overflow: hidden;
	background: #000;
}

.player-frame iframe {
	width: 100%;
	height: 100%;
	border: 0;
}

footer {
	border-top: 1px solid var(--border);
	padding: 28px 48px;
	display: flex;
	justify-content: space-between;
	align-items: center;
	gap: 12px;
	font-size: 12px;
	color: var(--muted);
	flex-wrap: wrap;
}

@media (max-width: 980px) {
	nav { padding: 16px 24px; }
	main { padding: 44px 20px 64px; }
}

@media (max-width: 760px) {
	.lecture-grid {
		grid-template-columns: 1fr;
	}

	.player-head h3 {
		font-size: 22px;
	}
}

@media (max-width: 680px) {
	nav {
		flex-wrap: wrap;
		gap: 12px;
		padding: 14px 16px;
	}

	.tagline { display: none; }

	.nav-links {
		display: grid;
		grid-template-columns: repeat(auto-fit, minmax(110px, 1fr));
		order: 3;
		width: 100%;
		gap: 8px;
		padding-top: 8px;
		border-top: 1px solid var(--border);
	}

	.nav-links a {
		display: inline-flex;
		align-items: center;
		justify-content: center;
		width: 100%;
		min-height: 36px;
		padding: 6px 8px;
		border: 1px solid var(--border);
		border-radius: 999px;
		background: #fff;
		color: var(--ink);
		font-weight: 500;
		font-size: 12px;
	}

	main {
		padding: 32px 14px 52px;
	}

	.lecture-card {
		padding: 16px;
	}

	.lecture-body h2 {
		font-size: 21px;
	}

	footer {
		padding: 20px 16px;
	}
}