:root {
	color-scheme: light dark;
	--bg-app: #fbf9f5;
	--bg-surface: #ffffff;
	--bg-surface-elevated: #f4f0e8;
	--bg-instructor: #f0f7f4;
	--border-instructor: #b8ded2;
	--fg-main: #1c2421;
	--fg-muted: #53645e;
	--fg-accent: #1e5e4b;
	--accent-primary: #2d7a64;
	--accent-hover: #236351;
	--accent-light: #e8f4f0;
	--accent-warm: #c86d38;
	--accent-warm-light: #fdf2eb;
	--border-subtle: #e2ddd3;
	--border-strong: #c5beae;
	--focus-ring: #005fcc;
	--radius-sm: 6px;
	--radius-md: 10px;
	--radius-lg: 16px;
	--radius-full: 9999px;
	--font-base: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
	--font-serif: "Georgia", "Cambria", "Times New Roman", serif;
	--font-size-scale: 1rem;
	--shadow-subtle: 0 2px 8px rgba(0, 0, 0, 0.04), 0 1px 2px rgba(0, 0, 0, 0.02);
	--shadow-card: 0 4px 16px rgba(0, 0, 0, 0.06), 0 1px 3px rgba(0, 0, 0, 0.04);
}

[data-theme="dark"] {
	--bg-app: #121816;
	--bg-surface: #1b2320;
	--bg-surface-elevated: #242e2b;
	--bg-instructor: #172a24;
	--border-instructor: #2d5549;
	--fg-main: #f0f4f2;
	--fg-muted: #a3b3ac;
	--fg-accent: #7ed4bc;
	--accent-primary: #3da386;
	--accent-hover: #4dbb9b;
	--accent-light: #1c332b;
	--accent-warm: #e0834c;
	--accent-warm-light: #332219;
	--border-subtle: #2d3834;
	--border-strong: #44544f;
	--focus-ring: #66b0ff;
	--shadow-subtle: 0 2px 8px rgba(0, 0, 0, 0.3);
	--shadow-card: 0 4px 16px rgba(0, 0, 0, 0.4);
}

[data-high-contrast="true"] {
	--bg-app: #000000 !important;
	--bg-surface: #000000 !important;
	--bg-surface-elevated: #1a1a1a !important;
	--bg-instructor: #051914 !important;
	--border-instructor: #00ffcc !important;
	--fg-main: #ffffff !important;
	--fg-muted: #e6e6e6 !important;
	--fg-accent: #ffff00 !important;
	--accent-primary: #ffff00 !important;
	--accent-hover: #ffffff !important;
	--accent-light: #222200 !important;
	--border-subtle: #ffffff !important;
	--border-strong: #ffffff !important;
	--focus-ring: #00ffff !important;
}

[data-font-size="large"] {
	font-size: 1.125rem;
}

[data-font-size="xlarge"] {
	font-size: 1.25rem;
}

* {
	box-sizing: border-box;
}

body {
	margin: 0;
	background: var(--bg-app);
	color: var(--fg-main);
	font-family: var(--font-base);
	line-height: 1.6;
	-webkit-font-smoothing: antialiased;
}

/* Visually hidden screen reader announcer */
.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;
}

/* Accessibility Focus Ring */
:focus-visible {
	outline: 3px solid var(--focus-ring);
	outline-offset: 3px;
}

/* App Container */
.app-container {
	max-width: 58rem;
	margin: 0 auto;
	padding: 1.25rem 1rem 4rem 1rem;
}

/* Header & Nav */
.header-bar {
	display: flex;
	flex-direction: column;
	gap: 0.75rem;
	padding-bottom: 1.25rem;
	margin-bottom: 1.5rem;
	border-bottom: 1px solid var(--border-subtle);
}

@media (min-width: 640px) {
	.header-bar {
		flex-direction: row;
		justify-content: space-between;
		align-items: center;
	}
}

.brand-section {
	display: flex;
	align-items: center;
	gap: 0.75rem;
}

.brand-icon {
	font-size: 2rem;
	line-height: 1;
	padding: 0.5rem;
	background: var(--accent-light);
	border-radius: var(--radius-md);
	border: 1px solid var(--border-instructor);
}

.brand-title {
	font-size: 1.35rem;
	font-weight: 700;
	margin: 0;
	letter-spacing: -0.01em;
	color: var(--fg-main);
}

.brand-subtitle {
	font-size: 0.85rem;
	color: var(--fg-muted);
	margin: 0;
}

.nav-controls {
	display: flex;
	align-items: center;
	gap: 0.5rem;
	flex-wrap: wrap;
}

.nav-btn {
	background: var(--bg-surface);
	color: var(--fg-main);
	border: 1px solid var(--border-subtle);
	padding: 0.45rem 0.85rem;
	border-radius: var(--radius-full);
	font-size: 0.875rem;
	font-weight: 600;
	cursor: pointer;
	transition: all 0.15s ease;
	display: inline-flex;
	align-items: center;
	gap: 0.35rem;
}

.nav-btn:hover {
	background: var(--bg-surface-elevated);
	border-color: var(--border-strong);
}

.nav-btn.active {
	background: var(--accent-primary);
	color: #ffffff;
	border-color: var(--accent-primary);
}

/* Disclaimer Banner */
.disclaimer-banner {
	background: var(--bg-surface-elevated);
	border: 1px solid var(--border-subtle);
	border-left: 4px solid var(--accent-warm);
	border-radius: var(--radius-sm);
	padding: 0.75rem 1rem;
	font-size: 0.825rem;
	color: var(--fg-muted);
	margin-bottom: 1.5rem;
	line-height: 1.5;
}

/* Cards & Surfaces */
.card-shell {
	background: var(--bg-surface);
	border: 1px solid var(--border-subtle);
	border-radius: var(--radius-lg);
	padding: 1.5rem;
	box-shadow: var(--shadow-card);
	margin-bottom: 1.5rem;
}

/* Instructor Message Bubble */
.instructor-bubble {
	background: var(--bg-instructor);
	border: 1px solid var(--border-instructor);
	border-radius: var(--radius-lg);
	padding: 1.25rem 1.5rem;
	margin-bottom: 1.5rem;
	position: relative;
}

.instructor-header {
	display: flex;
	align-items: center;
	justify-content: space-between;
	margin-bottom: 0.75rem;
	gap: 0.5rem;
	flex-wrap: wrap;
}

.instructor-badge {
	display: inline-flex;
	align-items: center;
	gap: 0.5rem;
	font-weight: 700;
	font-size: 0.95rem;
	color: var(--fg-accent);
}

.instructor-avatar {
	width: 28px;
	height: 28px;
	border-radius: 50%;
	background: var(--accent-primary);
	color: #ffffff;
	display: flex;
	align-items: center;
	justify-content: center;
	font-size: 0.85rem;
	font-weight: 700;
}

.instructor-text {
	font-size: 1.05rem;
	line-height: 1.65;
	color: var(--fg-main);
	margin: 0 0 0.75rem 0;
}

.concrete-direction-box {
	background: var(--bg-surface);
	border-left: 4px solid var(--accent-primary);
	border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
	padding: 0.85rem 1.15rem;
	margin-top: 0.75rem;
	font-size: 0.95rem;
	font-weight: 600;
	color: var(--fg-main);
}

.concrete-direction-label {
	display: block;
	font-size: 0.75rem;
	text-transform: uppercase;
	letter-spacing: 0.05em;
	color: var(--fg-accent);
	margin-bottom: 0.25rem;
	font-weight: 700;
}

/* Teaching Cycle / Step Status */
.teaching-cycle-bar {
	display: flex;
	align-items: center;
	gap: 0.5rem;
	background: var(--bg-surface-elevated);
	border: 1px solid var(--border-subtle);
	border-radius: var(--radius-md);
	padding: 0.5rem 0.85rem;
	margin-bottom: 1.25rem;
	font-size: 0.8rem;
	overflow-x: auto;
	white-space: nowrap;
}

.cycle-step {
	display: inline-flex;
	align-items: center;
	gap: 0.35rem;
	color: var(--fg-muted);
	font-weight: 500;
}

.cycle-step.current {
	color: var(--accent-primary);
	font-weight: 700;
}

.cycle-arrow {
	color: var(--border-strong);
}

/* Main Action Buttons Grid */
.teaching-controls-grid {
	display: grid;
	grid-template-columns: 1fr;
	gap: 0.75rem;
	margin-top: 1.5rem;
}

@media (min-width: 600px) {
	.teaching-controls-grid {
		grid-template-columns: repeat(2, 1fr);
	}
}

@media (min-width: 800px) {
	.teaching-controls-grid {
		grid-template-columns: repeat(3, 1fr);
	}
}

.action-btn {
	display: flex;
	flex-direction: column;
	align-items: flex-start;
	justify-content: center;
	padding: 0.9rem 1.1rem;
	border-radius: var(--radius-md);
	border: 1px solid var(--border-subtle);
	background: var(--bg-surface);
	color: var(--fg-main);
	cursor: pointer;
	text-align: left;
	transition: all 0.15s ease;
	min-height: 4.25rem;
}

.action-btn:hover {
	background: var(--bg-surface-elevated);
	border-color: var(--border-strong);
	transform: translateY(-1px);
}

.action-btn-title {
	font-size: 0.95rem;
	font-weight: 700;
	display: flex;
	align-items: center;
	gap: 0.4rem;
	margin-bottom: 0.15rem;
}

.action-btn-desc {
	font-size: 0.775rem;
	color: var(--fg-muted);
	line-height: 1.35;
}

.action-btn-ready {
	grid-column: 1 / -1;
	background: var(--accent-primary);
	color: #ffffff;
	border-color: var(--accent-primary);
	align-items: center;
	text-align: center;
	padding: 1.1rem;
}

.action-btn-ready:hover {
	background: var(--accent-hover);
	color: #ffffff;
}

.action-btn-ready .action-btn-desc {
	color: rgba(255, 255, 255, 0.9);
}

/* Audio & Practice Tools Section */
.practice-tools-panel {
	background: var(--bg-surface-elevated);
	border: 1px solid var(--border-subtle);
	border-radius: var(--radius-md);
	padding: 1rem 1.25rem;
	margin-top: 1.25rem;
}

.tools-title {
	font-size: 0.85rem;
	text-transform: uppercase;
	letter-spacing: 0.05em;
	font-weight: 700;
	color: var(--fg-muted);
	margin-bottom: 0.75rem;
}

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

.record-btn {
	display: inline-flex;
	align-items: center;
	gap: 0.5rem;
	padding: 0.5rem 1rem;
	border-radius: var(--radius-full);
	border: 1px solid var(--border-subtle);
	background: var(--bg-surface);
	color: var(--fg-main);
	font-weight: 600;
	font-size: 0.875rem;
	cursor: pointer;
}

.record-btn.recording {
	background: #dc2626;
	color: #ffffff;
	border-color: #b91c1c;
	animation: pulseRecord 1.5s infinite;
}

@keyframes pulseRecord {
	0% { opacity: 1; }
	50% { opacity: 0.75; }
	100% { opacity: 1; }
}

/* Camera Component */
.camera-container {
	background: #000000;
	border-radius: var(--radius-md);
	padding: 0.75rem;
	margin-top: 1rem;
	text-align: center;
}

.camera-video {
	width: 100%;
	max-height: 280px;
	object-fit: cover;
	border-radius: var(--radius-sm);
	transform: scaleX(-1); /* Mirror view */
}

.camera-cue-overlay {
	background: rgba(0, 0, 0, 0.8);
	color: #ffffff;
	border: 1px solid #444;
	border-radius: var(--radius-sm);
	padding: 0.6rem 0.9rem;
	margin-top: 0.5rem;
	font-size: 0.85rem;
	text-align: left;
}

/* Question & Dialog Box */
.dialog-card {
	background: var(--bg-surface);
	border: 1px solid var(--border-strong);
	border-radius: var(--radius-md);
	padding: 1.25rem;
	margin-top: 1rem;
}

.question-chip {
	display: inline-block;
	background: var(--bg-surface-elevated);
	border: 1px solid var(--border-subtle);
	border-radius: var(--radius-full);
	padding: 0.4rem 0.85rem;
	font-size: 0.825rem;
	margin: 0.25rem;
	cursor: pointer;
	text-align: left;
}

.question-chip:hover {
	background: var(--accent-light);
	border-color: var(--border-instructor);
}

/* Hub Grid */
.lesson-grid {
	display: grid;
	grid-template-columns: 1fr;
	gap: 1rem;
}

@media (min-width: 680px) {
	.lesson-grid {
		grid-template-columns: repeat(2, 1fr);
	}
}

.lesson-card {
	background: var(--bg-surface);
	border: 1px solid var(--border-subtle);
	border-radius: var(--radius-lg);
	padding: 1.25rem;
	cursor: pointer;
	transition: all 0.15s ease;
	display: flex;
	flex-direction: column;
	justify-content: space-between;
}

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

.lesson-card-header {
	display: flex;
	justify-content: space-between;
	align-items: flex-start;
	margin-bottom: 0.5rem;
}

.lesson-badge {
	font-size: 0.75rem;
	font-weight: 700;
	padding: 0.2rem 0.5rem;
	border-radius: var(--radius-sm);
	background: var(--accent-light);
	color: var(--accent-primary);
}

.lesson-title {
	font-size: 1.1rem;
	font-weight: 700;
	margin: 0 0 0.25rem 0;
	color: var(--fg-main);
}

.lesson-subtitle {
	font-size: 0.85rem;
	color: var(--fg-muted);
	margin: 0 0 0.75rem 0;
	line-height: 1.4;
}

.progress-pill {
	display: inline-flex;
	align-items: center;
	gap: 0.35rem;
	font-size: 0.775rem;
	font-weight: 600;
	color: var(--accent-primary);
}

/* Responsive Audio Meter Bars */
.audio-meter {
	display: flex;
	align-items: center;
	gap: 3px;
	height: 18px;
}

.meter-bar {
	width: 4px;
	height: 100%;
	background: var(--border-subtle);
	border-radius: 2px;
	transition: height 0.05s ease;
}

.meter-bar.active {
	background: var(--accent-primary);
}

/* Accessibility settings bar */
.settings-drawer {
	background: var(--bg-surface-elevated);
	border: 1px solid var(--border-subtle);
	border-radius: var(--radius-md);
	padding: 1rem;
	margin-bottom: 1.25rem;
}

.settings-grid {
	display: grid;
	grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
	gap: 0.75rem;
}

.setting-item {
	display: flex;
	flex-direction: column;
	gap: 0.35rem;
	font-size: 0.85rem;
}