:root {
	color-scheme: light dark;
	--bg: #0f172a;
	--bg-subtle: #1e293b;
	--bg-card: #1e293b;
	--bg-input: #0f172a;
	--fg: #f8fafc;
	--fg-muted: #94a3b8;
	--fg-subtle: #64748b;
	--accent: #3b82f6;
	--accent-hover: #2563eb;
	--accent-subtle: rgba(59, 130, 246, 0.15);
	--border: #334155;
	--border-light: #1e293b;
	--success: #10b981;
	--success-bg: rgba(16, 185, 129, 0.15);
	--warning: #f59e0b;
	--warning-bg: rgba(245, 158, 11, 0.15);
	--danger: #ef4444;
	--danger-bg: rgba(239, 68, 68, 0.15);
	--purple: #8b5cf6;
	--purple-bg: rgba(139, 92, 246, 0.15);
	--radius: 12px;
	--radius-sm: 8px;
	--radius-lg: 16px;
	--space: 1rem;
	--font: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
	--font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
	--shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -2px rgba(0, 0, 0, 0.3);
	--shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -4px rgba(0, 0, 0, 0.4);
}

@media (prefers-color-scheme: light) {
	:root {
		--bg: #f8fafc;
		--bg-subtle: #f1f5f9;
		--bg-card: #ffffff;
		--bg-input: #ffffff;
		--fg: #0f172a;
		--fg-muted: #475569;
		--fg-subtle: #94a3b8;
		--accent: #2563eb;
		--accent-hover: #1d4ed8;
		--accent-subtle: rgba(37, 99, 235, 0.1);
		--border: #e2e8f0;
		--border-light: #f1f5f9;
		--success: #059669;
		--success-bg: rgba(5, 150, 105, 0.1);
		--warning: #d97706;
		--warning-bg: rgba(217, 119, 6, 0.1);
		--danger: #dc2626;
		--danger-bg: rgba(220, 38, 38, 0.1);
		--purple: #7c3aed;
		--purple-bg: rgba(124, 58, 237, 0.1);
		--shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
		--shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.05);
	}
}

* {
	box-sizing: border-box;
}

body {
	margin: 0;
	background: var(--bg);
	color: var(--fg);
	font-family: var(--font);
	line-height: 1.55;
	-webkit-font-smoothing: antialiased;
}

.shell {
	max-width: 72rem;
	margin: 0 auto;
	padding: 1rem;
}

@media (min-width: 48rem) {
	.shell {
		padding: 1.5rem 2rem;
	}
}

/* Header & Navigation */
.app-header {
	background: var(--bg-card);
	border-bottom: 1px solid var(--border);
	position: sticky;
	top: 0;
	z-index: 40;
	backdrop-filter: blur(8px);
}

.app-nav-wrapper {
	max-width: 72rem;
	margin: 0 auto;
	padding: 0.75rem 1rem;
	display: flex;
	align-items: center;
	justify-content: space-between;
	flex-wrap: wrap;
	gap: 0.75rem;
}

.brand-group {
	display: flex;
	align-items: center;
	gap: 0.75rem;
	text-decoration: none;
	color: var(--fg);
	cursor: pointer;
}

.brand-logo {
	width: 2.25rem;
	height: 2.25rem;
	border-radius: var(--radius-sm);
	background: linear-gradient(135deg, var(--accent), var(--purple));
	display: flex;
	align-items: center;
	justify-content: center;
	font-weight: 800;
	color: #fff;
	font-size: 1.2rem;
	box-shadow: 0 2px 8px rgba(37, 99, 235, 0.3);
}

.brand-title-wrap {
	display: flex;
	flex-direction: column;
}

.brand-title {
	font-size: 1.15rem;
	font-weight: 700;
	line-height: 1.2;
	letter-spacing: -0.02em;
}

.brand-subtitle {
	font-size: 0.75rem;
	color: var(--fg-muted);
}

.nav-links {
	display: flex;
	align-items: center;
	gap: 0.35rem;
	flex-wrap: wrap;
}

.nav-btn {
	padding: 0.45rem 0.8rem;
	border-radius: var(--radius-sm);
	font-size: 0.875rem;
	font-weight: 500;
	color: var(--fg-muted);
	border: 1px solid transparent;
	background: transparent;
	cursor: pointer;
	display: inline-flex;
	align-items: center;
	gap: 0.4rem;
	transition: all 0.15s ease;
}

.nav-btn:hover {
	color: var(--fg);
	background: var(--bg-subtle);
}

.nav-btn.active {
	color: var(--accent);
	background: var(--accent-subtle);
	border-color: rgba(59, 130, 246, 0.3);
	font-weight: 600;
}

/* Typography & General Classes */
h1, h2, h3, h4, h5 {
	margin: 0 0 0.5rem;
	color: var(--fg);
	letter-spacing: -0.02em;
}

.lede {
	font-size: 1.05rem;
	color: var(--fg-muted);
	margin: 0 0 1rem;
}

.hint {
	font-size: 0.85rem;
	color: var(--fg-muted);
}

.btn {
	display: inline-flex;
	align-items: center;
	justify-content: center;
	gap: 0.45rem;
	padding: 0.55rem 1rem;
	border: 1px solid transparent;
	border-radius: var(--radius-sm);
	background: var(--accent);
	color: #ffffff;
	font: inherit;
	font-size: 0.9rem;
	font-weight: 600;
	cursor: pointer;
	transition: all 0.15s ease;
	text-decoration: none;
	user-select: none;
}

.btn:hover {
	background: var(--accent-hover);
	transform: translateY(-1px);
}

.btn:active {
	transform: translateY(0);
}

.btn-secondary {
	background: var(--bg-subtle);
	color: var(--fg);
	border-color: var(--border);
}

.btn-secondary:hover {
	background: var(--border);
	color: var(--fg);
}

.btn-outline {
	background: transparent;
	color: var(--accent);
	border-color: var(--accent);
}

.btn-outline:hover {
	background: var(--accent-subtle);
}

.btn-success {
	background: var(--success);
	color: #fff;
}
.btn-success:hover {
	background: #059669;
}

.btn-danger {
	background: var(--danger);
	color: #fff;
}
.btn-danger:hover {
	background: #dc2626;
}

.btn-warning {
	background: var(--warning);
	color: #1e293b;
}

.btn-sm {
	padding: 0.35rem 0.65rem;
	font-size: 0.8125rem;
}

.btn-lg {
	padding: 0.75rem 1.4rem;
	font-size: 1.05rem;
	font-weight: 700;
	border-radius: var(--radius);
}

.card {
	padding: 1.25rem;
	border: 1px solid var(--border);
	border-radius: var(--radius);
	background: var(--bg-card);
	box-shadow: var(--shadow);
}

.input, .select, .textarea {
	width: 100%;
	padding: 0.6rem 0.8rem;
	border: 1px solid var(--border);
	border-radius: var(--radius-sm);
	background: var(--bg-input);
	color: var(--fg);
	font: inherit;
	font-size: 0.925rem;
	transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.input:focus, .select:focus, .textarea:focus {
	outline: none;
	border-color: var(--accent);
	box-shadow: 0 0 0 3px var(--accent-subtle);
}

.field {
	display: grid;
	gap: 0.35rem;
	margin-bottom: 0.85rem;
}

.field > label {
	font-size: 0.875rem;
	font-weight: 600;
	color: var(--fg);
}

.stack {
	display: grid;
	gap: 1.25rem;
}

.row {
	display: flex;
	align-items: center;
	gap: 0.75rem;
	flex-wrap: wrap;
}

.grid {
	display: grid;
	gap: 1.25rem;
	grid-template-columns: repeat(auto-fit, minmax(min(18rem, 100%), 1fr));
}

.badge {
	display: inline-flex;
	align-items: center;
	gap: 0.3rem;
	padding: 0.15rem 0.6rem;
	border: 1px solid var(--border);
	border-radius: 999px;
	font-size: 0.75rem;
	font-weight: 600;
	color: var(--fg-muted);
	background: var(--bg-subtle);
}

.badge-blue {
	background: var(--accent-subtle);
	color: var(--accent);
	border-color: rgba(59, 130, 246, 0.3);
}

.badge-green {
	background: var(--success-bg);
	color: var(--success);
	border-color: rgba(16, 185, 129, 0.3);
}

.badge-warning {
	background: var(--warning-bg);
	color: var(--warning);
	border-color: rgba(245, 158, 11, 0.3);
}

.badge-danger {
	background: var(--danger-bg);
	color: var(--danger);
	border-color: rgba(239, 68, 68, 0.3);
}

.badge-purple {
	background: var(--purple-bg);
	color: var(--purple);
	border-color: rgba(139, 92, 246, 0.3);
}

/* Hero Section */
.hero-banner {
	background: linear-gradient(135deg, rgba(37, 99, 235, 0.15), rgba(139, 92, 246, 0.1));
	border: 1px solid var(--border);
	border-radius: var(--radius-lg);
	padding: 1.5rem;
	position: relative;
	overflow: hidden;
}

@media (min-width: 48rem) {
	.hero-banner {
		padding: 2.25rem;
	}
}

.hero-stats {
	display: flex;
	gap: 1rem;
	flex-wrap: wrap;
	margin-top: 1rem;
}

.hero-stat-pill {
	display: flex;
	align-items: center;
	gap: 0.5rem;
	background: var(--bg-card);
	border: 1px solid var(--border);
	border-radius: 999px;
	padding: 0.4rem 0.9rem;
	font-size: 0.85rem;
	font-weight: 600;
}

/* Exam Card Styles */
.exam-card {
	display: flex;
	flex-direction: column;
	justify-content: space-between;
	border: 1px solid var(--border);
	border-radius: var(--radius);
	background: var(--bg-card);
	padding: 1.25rem;
	transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
	position: relative;
}

.exam-card:hover {
	border-color: var(--accent);
	transform: translateY(-2px);
	box-shadow: var(--shadow-lg);
}

.exam-meta-row {
	display: flex;
	align-items: center;
	gap: 0.4rem;
	flex-wrap: wrap;
	margin-bottom: 0.75rem;
}

.exam-card-title {
	font-size: 1.15rem;
	font-weight: 700;
	line-height: 1.35;
	margin: 0 0 0.5rem;
}

.exam-details-list {
	display: flex;
	flex-direction: column;
	gap: 0.35rem;
	font-size: 0.85rem;
	color: var(--fg-muted);
	margin: 0.75rem 0 1.25rem;
}

.exam-details-list span {
	display: inline-flex;
	align-items: center;
	gap: 0.4rem;
}

.exam-card-actions {
	display: flex;
	align-items: center;
	gap: 0.5rem;
	margin-top: auto;
}

/* Filter Controls */
.filter-bar {
	background: var(--bg-card);
	border: 1px solid var(--border);
	border-radius: var(--radius);
	padding: 1rem;
	display: flex;
	flex-direction: column;
	gap: 0.75rem;
}

.filter-chips {
	display: flex;
	gap: 0.4rem;
	overflow-x: auto;
	padding-bottom: 0.25rem;
	scrollbar-width: thin;
}

.filter-chip {
	padding: 0.35rem 0.8rem;
	border-radius: 999px;
	font-size: 0.8125rem;
	font-weight: 600;
	border: 1px solid var(--border);
	background: var(--bg-subtle);
	color: var(--fg-muted);
	cursor: pointer;
	white-space: nowrap;
	transition: all 0.15s ease;
}

.filter-chip:hover {
	color: var(--fg);
	border-color: var(--accent);
}

.filter-chip.active {
	background: var(--accent);
	color: #fff;
	border-color: var(--accent);
}

/* Live Exam Taking Interface */
.exam-layout {
	display: grid;
	gap: 1.25rem;
	grid-template-columns: 1fr;
}

@media (min-width: 60rem) {
	.exam-layout {
		grid-template-columns: 1fr 20rem;
		align-items: start;
	}
}

.exam-top-bar {
	background: var(--bg-card);
	border: 1px solid var(--border);
	border-radius: var(--radius);
	padding: 0.85rem 1.25rem;
	display: flex;
	align-items: center;
	justify-content: space-between;
	flex-wrap: wrap;
	gap: 0.75rem;
	position: sticky;
	top: 4.2rem;
	z-index: 30;
	box-shadow: var(--shadow);
}

.timer-box {
	display: inline-flex;
	align-items: center;
	gap: 0.5rem;
	background: var(--bg-subtle);
	border: 1px solid var(--border);
	padding: 0.4rem 0.85rem;
	border-radius: var(--radius-sm);
	font-family: var(--font-mono);
	font-size: 1.15rem;
	font-weight: 700;
	color: var(--fg);
}

.timer-box.urgent {
	background: var(--danger-bg);
	border-color: var(--danger);
	color: var(--danger);
	animation: pulse 1s infinite;
}

@keyframes pulse {
	0%, 100% { transform: scale(1); }
	50% { transform: scale(1.03); }
}

.progress-track {
	width: 100%;
	height: 6px;
	background: var(--bg-subtle);
	border-radius: 999px;
	overflow: hidden;
}

.progress-fill {
	height: 100%;
	background: linear-gradient(90deg, var(--accent), var(--success));
	transition: width 0.3s ease;
}

/* Question Option Cards */
.question-container {
	background: var(--bg-card);
	border: 1px solid var(--border);
	border-radius: var(--radius);
	padding: 1.5rem;
	display: flex;
	flex-direction: column;
	gap: 1.25rem;
}

.question-text-box {
	font-size: 1.15rem;
	font-weight: 600;
	line-height: 1.5;
	color: var(--fg);
}

.options-list {
	display: grid;
	gap: 0.75rem;
}

.option-card {
	display: flex;
	align-items: flex-start;
	gap: 0.85rem;
	padding: 0.85rem 1rem;
	border: 2px solid var(--border);
	border-radius: var(--radius-sm);
	background: var(--bg-subtle);
	cursor: pointer;
	transition: all 0.15s ease;
	user-select: none;
}

.option-card:hover {
	border-color: var(--accent);
	background: var(--accent-subtle);
}

.option-card.selected {
	border-color: var(--accent);
	background: var(--accent-subtle);
	box-shadow: 0 0 0 1px var(--accent);
}

.option-letter {
	width: 1.75rem;
	height: 1.75rem;
	border-radius: 50%;
	background: var(--bg-card);
	border: 1px solid var(--border);
	display: flex;
	align-items: center;
	justify-content: center;
	font-size: 0.85rem;
	font-weight: 700;
	flex-shrink: 0;
	color: var(--fg);
	transition: all 0.15s ease;
}

.option-card.selected .option-letter {
	background: var(--accent);
	color: #fff;
	border-color: var(--accent);
}

.option-text {
	font-size: 0.95rem;
	line-height: 1.45;
	flex-grow: 1;
	color: var(--fg);
}

/* Navigation Palette / Grid */
.palette-card {
	background: var(--bg-card);
	border: 1px solid var(--border);
	border-radius: var(--radius);
	padding: 1rem;
	display: flex;
	flex-direction: column;
	gap: 1rem;
}

.palette-grid {
	display: grid;
	grid-template-columns: repeat(5, 1fr);
	gap: 0.4rem;
	max-height: 20rem;
	overflow-y: auto;
	padding: 0.2rem;
}

.palette-btn {
	height: 2.3rem;
	border-radius: var(--radius-sm);
	border: 1px solid var(--border);
	background: var(--bg-subtle);
	color: var(--fg-muted);
	font-size: 0.85rem;
	font-weight: 700;
	cursor: pointer;
	display: flex;
	align-items: center;
	justify-content: center;
	transition: all 0.1s ease;
	position: relative;
}

.palette-btn:hover {
	border-color: var(--accent);
	color: var(--fg);
}

.palette-btn.current {
	box-shadow: 0 0 0 2px var(--accent);
	border-color: var(--accent);
	font-weight: 800;
}

.palette-btn.answered {
	background: var(--success);
	color: #ffffff;
	border-color: var(--success);
}

.palette-btn.marked {
	background: var(--warning);
	color: #1e293b;
	border-color: var(--warning);
}

.palette-btn.answered.marked {
	background: var(--purple);
	color: #ffffff;
	border-color: var(--purple);
}

.palette-legend {
	display: grid;
	grid-template-columns: 1fr 1fr;
	gap: 0.5rem;
	font-size: 0.75rem;
	color: var(--fg-muted);
}

.legend-item {
	display: flex;
	align-items: center;
	gap: 0.4rem;
}

.legend-dot {
	width: 0.75rem;
	height: 0.75rem;
	border-radius: 3px;
	border: 1px solid var(--border);
}

/* Action Bars */
.exam-action-bar {
	display: flex;
	align-items: center;
	justify-content: space-between;
	gap: 0.5rem;
	flex-wrap: wrap;
	padding-top: 0.5rem;
}

/* Result Screen */
.result-hero {
	background: linear-gradient(135deg, rgba(37, 99, 235, 0.12), rgba(16, 185, 129, 0.12));
	border: 1px solid var(--border);
	border-radius: var(--radius-lg);
	padding: 2rem;
	text-align: center;
	display: flex;
	flex-direction: column;
	align-items: center;
	gap: 1rem;
}

.score-circle {
	width: 7.5rem;
	height: 7.5rem;
	border-radius: 50%;
	border: 6px solid var(--accent);
	display: flex;
	flex-direction: column;
	align-items: center;
	justify-content: center;
	background: var(--bg-card);
	box-shadow: var(--shadow-lg);
}

.score-num {
	font-size: 1.85rem;
	font-weight: 800;
	line-height: 1;
	color: var(--fg);
}

.score-pct {
	font-size: 0.85rem;
	color: var(--fg-muted);
	font-weight: 600;
}

.result-stats-grid {
	display: grid;
	grid-template-columns: repeat(auto-fit, minmax(8.5rem, 1fr));
	gap: 0.75rem;
	width: 100%;
}

.result-stat-card {
	background: var(--bg-card);
	border: 1px solid var(--border);
	border-radius: var(--radius);
	padding: 1rem;
	text-align: center;
}

.result-stat-val {
	font-size: 1.5rem;
	font-weight: 800;
	margin-bottom: 0.2rem;
}

.result-stat-lbl {
	font-size: 0.75rem;
	color: var(--fg-muted);
	font-weight: 600;
	text-transform: uppercase;
	letter-spacing: 0.05em;
}

/* Review Question Cards */
.review-card {
	background: var(--bg-card);
	border: 1px solid var(--border);
	border-radius: var(--radius);
	padding: 1.25rem;
	display: flex;
	flex-direction: column;
	gap: 0.85rem;
}

.review-card.correct {
	border-left: 5px solid var(--success);
}

.review-card.incorrect {
	border-left: 5px solid var(--danger);
}

.review-card.unanswered {
	border-left: 5px solid var(--warning);
}

.review-option {
	padding: 0.65rem 0.85rem;
	border-radius: var(--radius-sm);
	border: 1px solid var(--border);
	font-size: 0.9rem;
	display: flex;
	align-items: center;
	justify-content: space-between;
	gap: 0.5rem;
}

.review-option.is-correct {
	background: var(--success-bg);
	border-color: var(--success);
	color: var(--success);
	font-weight: 600;
}

.review-option.user-wrong {
	background: var(--danger-bg);
	border-color: var(--danger);
	color: var(--danger);
	text-decoration: line-through;
}

.explanation-box {
	background: var(--bg-subtle);
	border-left: 3px solid var(--accent);
	border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
	padding: 0.75rem 1rem;
	font-size: 0.875rem;
	color: var(--fg);
	line-height: 1.5;
}

/* Modal dialog */
.modal-overlay {
	position: fixed;
	inset: 0;
	background: rgba(0, 0, 0, 0.75);
	backdrop-filter: blur(4px);
	display: flex;
	align-items: center;
	justify-content: center;
	padding: 1rem;
	z-index: 100;
}

.modal-content {
	background: var(--bg-card);
	border: 1px solid var(--border);
	border-radius: var(--radius-lg);
	max-width: 32rem;
	width: 100%;
	padding: 1.5rem;
	box-shadow: var(--shadow-lg);
	display: flex;
	flex-direction: column;
	gap: 1.25rem;
	max-height: 90vh;
	overflow-y: auto;
}

/* Code Editor / JSON text */
.code-editor {
	width: 100%;
	min-height: 16rem;
	font-family: var(--font-mono);
	font-size: 0.85rem;
	line-height: 1.45;
	background: var(--bg-input);
	color: var(--fg);
	border: 1px solid var(--border);
	border-radius: var(--radius-sm);
	padding: 0.85rem;
	resize: vertical;
	tab-size: 2;
}

/* Alerts */
.alert {
	display: flex;
	align-items: flex-start;
	gap: 0.75rem;
	padding: 0.85rem 1rem;
	border: 1px solid var(--border);
	border-radius: var(--radius-sm);
	font-size: 0.875rem;
}

.alert-error {
	background: var(--danger-bg);
	border-color: rgba(239, 68, 68, 0.4);
	color: var(--danger);
}

.alert-warning {
	background: var(--warning-bg);
	border-color: rgba(245, 158, 11, 0.4);
	color: var(--warning);
}

.alert-success {
	background: var(--success-bg);
	border-color: rgba(16, 185, 129, 0.4);
	color: var(--success);
}

/* Utilities */
.loading {
	display: flex;
	align-items: center;
	justify-content: center;
	gap: 0.6rem;
	padding: 2rem;
	color: var(--fg-muted);
}

.spinner {
	width: 1.25rem;
	height: 1.25rem;
	border: 2px solid var(--border);
	border-top-color: var(--accent);
	border-radius: 50%;
	animation: fab-spin 0.7s linear infinite;
}

@keyframes fab-spin {
	to { transform: rotate(360deg); }
}

.empty {
	padding: 2.5rem 1rem;
	text-align: center;
	color: var(--fg-muted);
	display: flex;
	flex-direction: column;
	align-items: center;
	gap: 0.75rem;
}

.empty-title {
	font-size: 1.15rem;
	font-weight: 700;
	color: var(--fg);
	margin: 0;
}

/* Table */
.table-wrap {
	overflow-x: auto;
	border: 1px solid var(--border);
	border-radius: var(--radius);
}

.table {
	width: 100%;
	border-collapse: collapse;
	font-size: 0.875rem;
}

.table th, .table td {
	padding: 0.75rem 1rem;
	text-align: left;
	border-bottom: 1px solid var(--border);
}

.table th {
	background: var(--bg-subtle);
	color: var(--fg-muted);
	font-weight: 700;
	text-transform: uppercase;
	font-size: 0.75rem;
	letter-spacing: 0.04em;
}

.table tr:last-child td {
	border-bottom: none;
}

.table tr:hover td {
	background: var(--bg-subtle);
}

/* Tabs */
.tabs-nav {
	display: flex;
	gap: 0.35rem;
	border-bottom: 1px solid var(--border);
	padding-bottom: 0.25rem;
	overflow-x: auto;
	scrollbar-width: none;
}

.tab-btn {
	padding: 0.55rem 1rem;
	border: none;
	background: transparent;
	color: var(--fg-muted);
	font-size: 0.9rem;
	font-weight: 600;
	cursor: pointer;
	border-radius: var(--radius-sm);
	white-space: nowrap;
	display: flex;
	align-items: center;
	gap: 0.4rem;
	transition: all 0.15s ease;
}

.tab-btn:hover {
	color: var(--fg);
	background: var(--bg-subtle);
}

.tab-btn.active {
	color: var(--accent);
	background: var(--accent-subtle);
}