/* ============================================
   AI Tutor - Premium Design System
   ============================================ */

:root {
    /* Colors */
    --bg-primary: #0F0F23;
    --bg-secondary: #1A1A2E;
    --bg-card: #252540;
    --bg-elevated: #2D2D4A;

    --accent-primary: #6366F1;
    --accent-secondary: #8B5CF6;
    --accent-pink: #EC4899;
    --accent-cyan: #06B6D4;
    --accent-green: #10B981;
    --accent-red: #EF4444;

    --text-primary: #FFFFFF;
    --text-secondary: #A1A1AA;
    --text-muted: #71717A;

    --glass-bg: rgba(255, 255, 255, 0.08);
    --glass-border: rgba(255, 255, 255, 0.15);

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #6366F1, #8B5CF6);
    --gradient-pink: linear-gradient(135deg, #EC4899, #F43F5E);
    --gradient-cyan: linear-gradient(135deg, #06B6D4, #3B82F6);
    --gradient-green: linear-gradient(135deg, #10B981, #34D399);

    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    --spacing-2xl: 48px;

    /* Layout spacing multiplier */
    --layout-spacing: 1;

    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 40px rgba(99, 102, 241, 0.3);

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* ============================================
   Reset & Base Styles
   ============================================ */

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

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    overflow-x: hidden;
    line-height: 1.5;
}

html.no-scroll,
html.no-scroll body {
    overflow: hidden;
    height: 100%;
    height: 100dvh;
}

/* ============================================
   Animated Background
   ============================================ */

.background-orbs {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
    overflow: hidden;
}

.orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(60px);
    animation: float 8s ease-in-out infinite;
}

.orb-1 {
    width: 300px;
    height: 300px;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.4), transparent 70%);
    top: -100px;
    left: -100px;
    animation-delay: 0s;
}

.orb-2 {
    width: 250px;
    height: 250px;
    background: radial-gradient(circle, rgba(236, 72, 153, 0.3), transparent 70%);
    top: 50%;
    right: -80px;
    animation-delay: -3s;
}

.orb-3 {
    width: 200px;
    height: 200px;
    background: radial-gradient(circle, rgba(6, 182, 212, 0.25), transparent 70%);
    bottom: -50px;
    left: 30%;
    animation-delay: -5s;
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0) rotate(0deg);
    }

    50% {
        transform: translateY(30px) rotate(5deg);
    }
}

/* ============================================
   App Container
   ============================================ */

#app {
    position: relative;
    z-index: 1;
    min-height: 100vh;
}

.screen {
    display: none;
    min-height: 100vh;
}

.screen.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

#main-screen.active {
    display: flex;
    flex-direction: column;
    height: 100vh;
    height: 100dvh;
    overflow: hidden;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ============================================
   Glass Card Effect
   ============================================ */

.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
}

/* ============================================
   Onboarding Screen
   ============================================ */

.onboarding-container {
    max-width: 480px;
    margin: 0 auto;
    padding: var(--spacing-xl);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: var(--spacing-sm);
}

.logo-container {
    text-align: center;
    margin-bottom: var(--spacing-md);
}

.logo-icon {
    width: 100px;
    height: 100px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--spacing-lg);
    box-shadow: var(--shadow-glow);
    animation: pulse 3s ease-in-out infinite;
}

.logo-icon svg {
    width: 50px;
    height: 50px;
    color: white;
}

@keyframes pulse {

    0%,
    100% {
        box-shadow: var(--shadow-glow);
    }

    50% {
        box-shadow: 0 0 60px rgba(99, 102, 241, 0.5);
    }
}

.app-title {
    font-size: 2.5rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.app-subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin-top: var(--spacing-xs);
}

.features-list {
    padding: var(--spacing-sm) var(--spacing-lg);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.feature-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.feature-icon {
    font-size: 1.5rem;
    width: 40px;
    text-align: center;
}

.feature-text {
    display: flex;
    flex-direction: column;
}

.feature-text strong {
    font-weight: 600;
    color: var(--text-primary);
}

.feature-text span {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.setup-form {
    padding: var(--spacing-lg);
}

.setup-form h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-lg);
}

.form-group {
    margin-bottom: var(--spacing-md);
}

.form-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
}

.form-hint {
    font-weight: 400;
    color: var(--text-muted);
    font-size: 0.8rem;
}

.form-select {
    width: 100%;
    padding: var(--spacing-md);
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 1rem;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition-fast);
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 24 24' fill='none' stroke='%23A1A1AA' stroke-width='2'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
}

.form-select:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.form-select:hover {
    border-color: var(--accent-primary);
}

/* ============================================
   Buttons
   ============================================ */

.primary-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    width: 100%;
    padding: var(--spacing-md) var(--spacing-xl);
    background: var(--gradient-primary);
    border: none;
    border-radius: var(--radius-lg);
    color: white;
    font-size: 1.1rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition-normal);
    box-shadow: 0 4px 20px rgba(99, 102, 241, 0.4);
}

.primary-btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 30px rgba(99, 102, 241, 0.5);
}

.primary-btn:active:not(:disabled) {
    transform: translateY(0);
}

.primary-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    box-shadow: none;
}

.primary-btn svg {
    width: 20px;
    height: 20px;
}

.secondary-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    width: 100%;
    padding: var(--spacing-md) var(--spacing-xl);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    color: var(--text-primary);
    font-size: 1rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition-normal);
}

.secondary-btn:hover {
    background: rgba(255, 255, 255, 0.12);
    border-color: var(--accent-primary);
}

.text-btn {
    background: none;
    border: none;
    color: var(--accent-red);
    font-size: 1rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    padding: var(--spacing-sm) var(--spacing-md);
    transition: var(--transition-fast);
}

.text-btn:hover {
    opacity: 0.8;
}

.back-btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    background: none;
    border: none;
    color: var(--accent-primary);
    font-size: 1rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    padding: var(--spacing-sm);
    transition: var(--transition-fast);
}

.back-btn svg {
    width: 20px;
    height: 20px;
}

.back-btn:hover {
    opacity: 0.8;
}

.icon-btn {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-sm);
    color: var(--accent-primary);
    cursor: pointer;
    transition: var(--transition-fast);
}

.icon-btn svg {
    width: 20px;
    height: 20px;
}

.icon-btn:hover {
    background: rgba(255, 255, 255, 0.12);
}

/* ============================================
   Main Navigation
   ============================================ */

.main-nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--glass-border);
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.25rem;
    font-weight: 700;
}

.nav-logo {
    font-size: 1.5rem;
}

.nav-user {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    font-size: 0.875rem;
}

.user-grade {
    background: var(--gradient-primary);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    font-weight: 500;
}

.user-location {
    color: var(--text-secondary);
}

/* ============================================
   Tab Navigation
   ============================================ */

.tab-nav {
    display: flex;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--glass-border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.tab-btn {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-md);
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: 0.75rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition-fast);
    position: relative;
}

.tab-btn svg {
    width: 24px;
    height: 24px;
}

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

.tab-btn.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 40px;
    height: 3px;
    background: var(--gradient-primary);
    border-radius: var(--radius-full);
}

.tab-btn:hover:not(.active) {
    color: var(--text-secondary);
}

/* ============================================
   Tab Panels
   ============================================ */

.tab-content {
    flex: 1;
    min-height: 0;
    display: flex;
    flex-direction: column;
    overflow: auto;
    padding-bottom: 100px;
}

.tab-content:has(#capture-tab.active) {
    padding-bottom: 0;
}

.tab-panel {
    display: none;
    padding: var(--spacing-lg);
    max-width: 800px;
    margin: 0 auto;
}

.tab-panel.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

#capture-tab.active {
    display: flex;
    flex-direction: column;
    padding: 0;
    max-width: none;
    margin: 0;
    flex: 1;
    min-height: 0;
}

/* ============================================
   Home Tab
   ============================================ */

.home-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.home-header h2 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
}

.home-header p {
    color: var(--text-secondary);
}

.quick-actions {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.action-card {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-lg);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    cursor: pointer;
    transition: var(--transition-normal);
    text-align: left;
    width: 100%;
}

.action-card:hover {
    transform: translateX(4px);
    border-color: var(--accent-primary);
    background: rgba(255, 255, 255, 0.1);
}

.action-icon {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.action-icon svg {
    width: 28px;
    height: 28px;
    color: white;
}

.gradient-purple {
    background: var(--gradient-primary);
}

.gradient-pink {
    background: var(--gradient-pink);
}

.gradient-cyan {
    background: var(--gradient-cyan);
}

.action-text {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.action-text strong {
    font-size: 1.1rem;
    font-weight: 600;
}

.action-text span {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.action-hint {
    margin-top: 2px;
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-weight: 400;
}

.action-arrow {
    width: 20px;
    height: 20px;
    color: var(--text-muted);
}

.tips-card {
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.tips-card h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

.tip-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-sm) 0;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.tip-dot {
    width: 8px;
    height: 8px;
    background: var(--accent-primary);
    border-radius: 50%;
    flex-shrink: 0;
}

.recent-sessions h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

.sessions-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.session-card {
    display: flex;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: var(--transition-fast);
}

.session-card:hover {
    border-color: var(--accent-primary);
    background: rgba(255, 255, 255, 0.1);
}

.session-thumb {
    width: 60px;
    height: 60px;
    border-radius: var(--radius-md);
    object-fit: cover;
    background: var(--bg-card);
}

.session-thumb-quiz {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.session-info {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.session-info strong {
    font-size: 0.95rem;
    margin-bottom: var(--spacing-xs);
}

.session-info span {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.session-delete {
    align-self: center;
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: var(--spacing-sm);
    transition: var(--transition-fast);
}

.session-delete:hover {
    color: var(--accent-red);
}

.session-delete svg {
    width: 18px;
    height: 18px;
    display: block;
}

.empty-state {
    text-align: center;
    padding: var(--spacing-xl);
    color: var(--text-muted);
    font-style: italic;
}

/* ============================================
   Capture Tab
   ============================================ */

.capture-container {
    display: flex;
    flex-direction: column;
    flex: 1;
    min-height: 0;
}

.camera-area {
    flex: 1;
    min-height: 0;
    position: relative;
    background: var(--bg-card);
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
}

#camera-video {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* Portrait: camera area fills the screen */
@media (orientation: portrait) {
    .tab-content:has(#capture-tab.active) {
        display: flex;
        flex-direction: column;
        flex: 1;
        min-height: 0;
    }
    #capture-tab.active {
        flex: 1;
        min-height: 0;
    }
    .capture-container {
        flex: 1;
        min-height: 0;
        display: flex;
        flex-direction: column;
    }
    .camera-area {
        flex: 1;
        min-height: 0;
        width: 100%;
    }
    .camera-area #camera-video {
        width: 100%;
        height: 100%;
        object-fit: cover;
        object-position: center;
    }
}

.camera-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    pointer-events: none;
}

.camera-frame {
    width: 80%;
    height: 60%;
    border: 2px dashed rgba(255, 255, 255, 0.3);
    border-radius: var(--radius-lg);
}

.camera-instructions {
    position: absolute;
    top: 90px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(0, 0, 0, 0.7);
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-full);
    font-size: 0.9rem;
    color: white;
    z-index: 2;
}

.camera-controls {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
}

.camera-controls-top {
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--glass-border);
}

.camera-controls-overlay {
    position: absolute;
    top: var(--spacing-md);
    left: 0;
    right: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-lg);
    z-index: 3;
}

.camera-btn {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 50%;
    cursor: pointer;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

.camera-btn.secondary {
    width: 50px;
    height: 50px;
    color: white;
}

.camera-btn.secondary svg {
    width: 24px;
    height: 24px;
}

.camera-btn.capture {
    width: 68px;
    height: 68px;
    background: transparent;
    border: 3px solid white;
    padding: 4px;
}

.shutter-ring {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    height: 100%;
}

.shutter-circle {
    width: 100%;
    height: 100%;
    background: white;
    border-radius: 50%;
    transition: var(--transition-fast);
}

.camera-btn.capture:active .shutter-circle {
    transform: scale(0.85);
    background: rgba(255, 255, 255, 0.8);
}

.camera-btn.secondary:hover {
    background: rgba(255, 255, 255, 0.15);
}

.camera-btn.capture {
    width: 80px;
    height: 80px;
    background: white;
    border: 4px solid white;
    padding: 4px;
}

.capture-ring {
    width: 100%;
    height: 100%;
    border-radius: 50%;
    background: white;
    transition: var(--transition-fast);
}

.camera-btn.capture:hover .capture-ring {
    transform: scale(0.9);
}

.camera-btn.capture:active .capture-ring {
    transform: scale(0.8);
    background: var(--text-secondary);
}

/* ============================================
   History Tab
   ============================================ */

.history-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.history-header h2 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
}

.history-header p {
    color: var(--text-secondary);
}

.history-clear-btn {
    margin-top: var(--spacing-md);
    width: auto;
    display: inline-flex;
    gap: var(--spacing-sm);
}

.history-clear-btn svg {
    flex-shrink: 0;
}

.history-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.history-card {
    display: flex;
    gap: var(--spacing-md);
    padding: var(--spacing-lg);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    cursor: pointer;
    transition: var(--transition-fast);
}

.history-card:hover {
    border-color: var(--accent-primary);
    transform: translateX(4px);
}

.history-image {
    width: 80px;
    height: 80px;
    border-radius: var(--radius-md);
    object-fit: cover;
    background: var(--bg-card);
}

.history-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.history-content h4 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.history-session-id {
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text-muted);
    margin-right: 0.35em;
}

.history-content p {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xs);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.history-meta {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.history-delete {
    align-self: flex-start;
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: var(--spacing-sm);
    transition: var(--transition-fast);
}

.history-delete:hover {
    color: var(--accent-red);
}

.history-delete svg {
    width: 18px;
    height: 18px;
}

/* ============================================
   Settings Tab
   ============================================ */

.settings-container {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.settings-profile {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-xl) 0;
}

.profile-avatar {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.profile-avatar svg {
    width: 40px;
    height: 40px;
    color: white;
}

.profile-info {
    text-align: center;
}

.profile-info h3 {
    font-size: 1.25rem;
    font-weight: 600;
}

.profile-info p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.settings-section {
    padding: var(--spacing-lg);
}

.settings-section h4 {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    color: var(--text-muted);
    margin-bottom: var(--spacing-md);
    letter-spacing: 0.05em;
}

.settings-row {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md) 0;
    cursor: pointer;
    transition: var(--transition-fast);
    border-bottom: 1px solid var(--glass-border);
}

.settings-row:last-child {
    border-bottom: none;
}

.settings-row:hover {
    opacity: 0.8;
}

.settings-row.danger .settings-row-text strong {
    color: var(--accent-red);
}

.settings-row-icon {
    font-size: 1.25rem;
    width: 30px;
    text-align: center;
}

.settings-row-text {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.settings-row-text strong {
    font-size: 1rem;
    font-weight: 500;
}

.settings-row-text span {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.settings-row>svg {
    width: 16px;
    height: 16px;
    color: var(--text-muted);
}

#reset-app {
    margin-top: var(--spacing-md);
    color: var(--accent-red);
    border-color: var(--accent-red);
}

#reset-app:hover {
    background: rgba(239, 68, 68, 0.1);
}

/* API Key Settings */
.api-key-setting {
    display: flex;
    gap: var(--spacing-md);
    padding: var(--spacing-md) 0;
}

.api-key-input-group {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.api-key-input-group label {
    font-weight: 500;
    font-size: 1rem;
}

.api-key-field {
    display: flex;
    gap: var(--spacing-sm);
}

.api-key-field .form-input {
    flex: 1;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 0.9rem;
    font-family: 'Courier New', monospace;
}

.api-key-field .form-input:focus {
    outline: none;
    border-color: var(--accent-primary);
}

.api-key-hint {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.api-key-hint.success {
    color: var(--accent-green);
}

.api-key-hint.error {
    color: var(--accent-red);
}

#save-api-key {
    margin-top: var(--spacing-sm);
}

/* ============================================
   Annotation Screen
   ============================================ */

#annotation-screen {
    display: none;
    flex-direction: column;
    height: 100vh;
    height: 100dvh;
    background: var(--bg-primary);
}

#annotation-screen.active {
    display: flex;
}

.annotation-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--glass-border);
}

.annotation-header h3 {
    font-size: 1.1rem;
    font-weight: 600;
}

.annotation-canvas-container {
    flex: 1;
    min-height: 0;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    background: var(--bg-card);
}

#annotation-image {
    max-width: 100%;
    max-height: 100%;
    width: auto;
    height: auto;
    object-fit: contain;
    z-index: 1;
}

#annotation-canvas {
    position: absolute;
    top: 0;
    left: 0;
    cursor: crosshair;
    z-index: 2;
}

.annotation-controls {
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border-top: 1px solid var(--glass-border);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.brush-size-control {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.brush-icon {
    color: var(--text-secondary);
}

.brush-icon.small {
    width: 16px;
    height: 16px;
}

.brush-icon.large {
    width: 24px;
    height: 24px;
}

#brush-size {
    flex: 1;
    -webkit-appearance: none;
    appearance: none;
    height: 4px;
    background: var(--bg-card);
    border-radius: var(--radius-full);
    outline: none;
}

#brush-size::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    background: var(--accent-red);
    border-radius: 50%;
    cursor: pointer;
    box-shadow: 0 2px 8px rgba(239, 68, 68, 0.4);
}

#brush-size::-moz-range-thumb {
    width: 20px;
    height: 20px;
    background: var(--accent-red);
    border-radius: 50%;
    cursor: pointer;
    border: none;
}

.annotation-hint {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    justify-content: center;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.red-dot {
    width: 12px;
    height: 12px;
    background: var(--accent-red);
    border-radius: 50%;
}

/* ============================================
   Question/Chat Screen
   ============================================ */

#question-screen {
    display: none;
    flex-direction: column;
    height: 100vh;
    height: 100dvh;
    background: var(--bg-primary);
    overflow: hidden;
}

#question-screen.active {
    display: flex;
}

/* Keeps header and input visible: body takes remaining space, only messages scroll */
.question-screen-body {
    flex: 1;
    min-height: 0;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.chat-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--glass-border);
    flex-shrink: 0;
}

.chat-title {
    flex: 1;
    text-align: center;
}

.chat-title h3 {
    font-size: 1.1rem;
    font-weight: 600;
}

.chat-title span {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.chat-title .chat-location {
    color: var(--text-secondary);
}

.chat-title .chat-session-id {
    display: block;
    font-size: 0.7rem;
    color: var(--text-muted);
    font-family: ui-monospace, monospace;
}

.chat-messages {
    flex: 1;
    min-height: 0;
    /* Important for flex child scrolling */
    overflow-y: auto;
    overflow-x: hidden;
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    scroll-behavior: smooth;
}

.message {
    display: flex;
    flex-direction: column;
    max-width: 85%;
}

.message:has(.message-image) {
    max-width: 100%;
}

.message.user {
    align-self: flex-end;
}

.message.assistant {
    align-self: flex-start;
}

.message-content {
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* Code styling in messages */
.message-content code {
    background: rgba(0, 0, 0, 0.3);
    padding: 2px 6px;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-size: 0.9em;
}

/* Math formula styling */
.message-content .katex-display {
    margin: var(--spacing-md) 0;
    padding: var(--spacing-md);
    background: rgba(0, 0, 0, 0.2);
    border-radius: var(--radius-md);
    overflow-x: auto;
}

.message-content .katex {
    font-size: 1.1em;
}

.message.assistant .message-content .katex-display {
    background: rgba(255, 255, 255, 0.05);
}

.message.user .message-content {
    background: var(--accent-primary);
    color: white;
    border-bottom-right-radius: var(--spacing-xs);
}

.message.assistant .message-content {
    background: var(--bg-card);
    color: var(--text-primary);
    border-bottom-left-radius: var(--spacing-xs);
}

.message-time {
    font-size: 0.7rem;
    color: var(--text-muted);
    margin-top: var(--spacing-xs);
    padding: 0 var(--spacing-sm);
}

.token-usage {
    display: block;
    margin-top: var(--spacing-sm);
    font-size: 0.65rem;
    color: var(--text-muted);
    opacity: 0.6;
}

.message.user .message-time {
    text-align: right;
}

.message-image {
    max-width: 100%;
    width: auto;
    height: auto;
    max-height: 40dvh;
    object-fit: contain;
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-sm);
    display: block;
}

.typing-indicator {
    display: flex;
    gap: 4px;
    padding: var(--spacing-md);
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    width: fit-content;
}

.typing-indicator span {
    width: 8px;
    height: 8px;
    background: var(--text-muted);
    border-radius: 50%;
    animation: typing 1.4s infinite ease-in-out;
}

.typing-indicator span:nth-child(2) {
    animation-delay: 0.2s;
}

.typing-indicator span:nth-child(3) {
    animation-delay: 0.4s;
}

@keyframes typing {

    0%,
    60%,
    100% {
        transform: translateY(0);
    }

    30% {
        transform: translateY(-4px);
    }
}

.quick-suggestions {
    display: flex;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    overflow-x: auto;
    scrollbar-width: none;
    flex-shrink: 0;
}

.quick-suggestions::-webkit-scrollbar {
    display: none;
}

.suggestion-chip {
    flex-shrink: 0;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--glass-bg);
    border: 1px solid var(--accent-primary);
    border-radius: var(--radius-full);
    color: var(--accent-primary);
    font-size: 0.875rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition-fast);
    white-space: nowrap;
}

.suggestion-chip:hover {
    background: rgba(99, 102, 241, 0.2);
}

.quiz-subjects {
    display: none;
    flex-direction: column;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-lg);
    flex-shrink: 0;
    border-top: 1px solid var(--glass-border);
}

.quiz-subjects-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.quiz-subjects-chips {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.quiz-subjects-chips .suggestion-chip {
    margin: 0;
}

/* Quiz multiple-choice buttons — just A B C D in a row */
.quiz-choices {
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}
.quiz-choice-btn {
    width: 2.4rem;
    height: 2.4rem;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--glass-bg);
    border: 1.5px solid var(--accent-primary);
    border-radius: 50%;
    color: var(--accent-primary);
    font-size: 1rem;
    font-weight: 700;
    cursor: pointer;
    transition: background 0.15s, color 0.15s;
    flex-shrink: 0;
}
.quiz-choice-btn:hover {
    background: var(--accent-primary);
    color: #fff;
}

/* Easier / Harder / Quit inline with A B C D */
.quiz-actions-inline {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-left: auto;
    flex-shrink: 0;
}
.quiz-choices .quiz-action-btn {
    padding: var(--spacing-xs) var(--spacing-md);
    font-size: 0.75rem;
}
.quiz-choices .quiz-action-exit {
    margin-left: 0;
}

/* Quiz toolbar: Easier / Harder / Exit (same line) — used when no choices yet (topic selection) */
.quiz-actions {
    display: none;
    flex-wrap: nowrap;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    border-top: 1px solid var(--glass-border);
    background: var(--bg-secondary);
    flex-shrink: 0;
}
.quiz-action-btn {
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    color: var(--text-primary);
    font-size: 0.8rem;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.15s, border-color 0.15s;
}
.quiz-action-btn:hover {
    background: rgba(99, 102, 241, 0.15);
    border-color: var(--accent-primary);
}
.quiz-action-exit {
    margin-left: auto;
    border-color: rgba(239, 68, 68, 0.5);
    color: var(--text-primary);
}
.quiz-action-exit:hover {
    background: rgba(239, 68, 68, 0.15);
    border-color: rgba(239, 68, 68, 0.8);
}

.chat-input-container {
    display: flex;
    align-items: flex-end;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    padding-bottom: calc(var(--spacing-md) + env(safe-area-inset-bottom, 0px));
    background: var(--bg-secondary);
    border-top: 1px solid var(--glass-border);
    flex-shrink: 0;
}

#chat-input {
    flex: 1;
    padding: var(--spacing-md);
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    color: var(--text-primary);
    font-size: 1rem;
    font-family: inherit;
    resize: none;
    max-height: 120px;
    transition: var(--transition-fast);
}

#chat-input:focus {
    outline: none;
    border-color: var(--accent-primary);
}

#chat-input::placeholder {
    color: var(--text-muted);
}

.send-btn {
    width: 48px;
    height: 48px;
    background: var(--gradient-primary);
    border: none;
    border-radius: 50%;
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition-fast);
    flex-shrink: 0;
}

.send-btn svg {
    width: 20px;
    height: 20px;
}

.send-btn:hover:not(:disabled) {
    transform: scale(1.05);
    box-shadow: 0 4px 20px rgba(99, 102, 241, 0.4);
}

.send-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* ============================================
   Modals
   ============================================ */

.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-lg);
}

.modal.active {
    display: flex;
    animation: fadeIn 0.2s ease;
}

.modal-content {
    width: 100%;
    max-width: 400px;
    max-height: 80vh;
    overflow-y: auto;
    padding: var(--spacing-xl);
}

.modal-content h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-lg);
    text-align: center;
}

.form-input {
    width: 100%;
    padding: var(--spacing-md);
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 1rem;
    font-family: inherit;
    transition: var(--transition-fast);
}

.form-input:focus {
    outline: none;
    border-color: var(--accent-primary);
}

.error-text {
    color: var(--accent-red);
    font-size: 0.85rem;
    margin-top: var(--spacing-sm);
    text-align: center;
    min-height: 20px;
}

.grade-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
}

.grade-btn {
    padding: var(--spacing-md);
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 1.1rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition-fast);
}

.grade-btn:hover {
    border-color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.1);
}

.grade-btn.selected {
    background: var(--gradient-primary);
    border-color: transparent;
}

.modal-actions {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.modal-actions button {
    flex: 1;
}

/* ============================================
   Responsive Design
   ============================================ */

@media (min-width: 768px) {
    .onboarding-container {
        padding: var(--spacing-2xl);
    }

    .tab-nav {
        justify-content: center;
        gap: var(--spacing-xl);
    }

    .tab-btn {
        flex: none;
        padding: var(--spacing-md) var(--spacing-xl);
        flex-direction: row;
        gap: var(--spacing-sm);
    }

    .quick-actions {
        flex-direction: row;
    }

    .action-card {
        flex: 1;
    }

    .history-list {
        display: grid;
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 480px) {
    .nav-user {
        flex-direction: column;
        align-items: flex-end;
        gap: var(--spacing-xs);
    }

    .user-location {
        font-size: 0.75rem;
    }

    .camera-controls {
        gap: var(--spacing-lg);
    }

    .camera-btn.capture {
        width: 70px;
        height: 70px;
    }
}

/* ============================================
   Utilities
   ============================================ */

.hidden {
    display: none !important;
}

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

/* ============================================
   Theme Colors
   ============================================ */

/* Blue Theme */
[data-theme="blue"] {
    --accent-primary: #3B82F6;
    --accent-secondary: #06B6D4;
    --gradient-primary: linear-gradient(135deg, #3B82F6, #06B6D4);
}

[data-theme="blue"] .orb-1 {
    background: radial-gradient(circle, rgba(59, 130, 246, 0.4), transparent);
}

[data-theme="blue"] .orb-2 {
    background: radial-gradient(circle, rgba(6, 182, 212, 0.3), transparent);
}

/* Green Theme */
[data-theme="green"] {
    --accent-primary: #10B981;
    --accent-secondary: #34D399;
    --gradient-primary: linear-gradient(135deg, #10B981, #34D399);
}

[data-theme="green"] .orb-1 {
    background: radial-gradient(circle, rgba(16, 185, 129, 0.4), transparent);
}

[data-theme="green"] .orb-2 {
    background: radial-gradient(circle, rgba(52, 211, 153, 0.3), transparent);
}

/* ============================================
   Layout Modes
   ============================================ */

/* Compact Layout */
[data-layout="compact"] {
    --spacing-xs: 2px;
    --spacing-sm: 6px;
    --spacing-md: 12px;
    --spacing-lg: 18px;
    --spacing-xl: 24px;
    --spacing-2xl: 36px;
}

[data-layout="compact"] .glass-card {
    padding: var(--spacing-md);
}

[data-layout="compact"] .message-content {
    padding: var(--spacing-sm) var(--spacing-md);
}

/* Spacious Layout */
[data-layout="spacious"] {
    --spacing-xs: 6px;
    --spacing-sm: 12px;
    --spacing-md: 20px;
    --spacing-lg: 32px;
    --spacing-xl: 44px;
    --spacing-2xl: 64px;
}

[data-layout="spacious"] .glass-card {
    padding: var(--spacing-lg);
}

[data-layout="spacious"] .message-content {
    padding: var(--spacing-md) var(--spacing-lg);
}

/* ============================================
   Appearance Settings UI
   ============================================ */

.appearance-setting {
    padding: var(--spacing-md) 0;
    border-bottom: 1px solid var(--glass-border);
}

.appearance-setting:last-child {
    border-bottom: none;
}

.appearance-setting label {
    display: block;
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.appearance-setting:has(.toggle-switch) {
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.appearance-setting:has(.toggle-switch) > label:first-child {
    margin-bottom: 0;
}

.toggle-switch {
    position: relative;
    display: inline-block;
    width: 44px;
    height: 24px;
    margin-bottom: 0 !important;
}
.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}
.toggle-slider {
    position: absolute;
    inset: 0;
    background: rgba(255,255,255,0.15);
    border-radius: 24px;
    cursor: pointer;
    transition: background 0.2s;
}
.toggle-slider::before {
    content: '';
    position: absolute;
    width: 18px;
    height: 18px;
    left: 3px;
    bottom: 3px;
    background: white;
    border-radius: 50%;
    transition: transform 0.2s;
}
.toggle-switch input:checked + .toggle-slider {
    background: var(--accent-primary);
}
.toggle-switch input:checked + .toggle-slider::before {
    transform: translateX(20px);
}

.theme-options,
.layout-options {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.theme-option {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm);
    background: transparent;
    border: 2px solid var(--glass-border);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.2s ease;
    min-width: 60px;
    flex: 1 1 60px;
    max-width: calc(33.333% - var(--spacing-md));
}

.theme-option:hover {
    border-color: var(--text-muted);
    background: var(--glass-bg);
}

.theme-option.active {
    border-color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.1);
}

.theme-preview {
    width: 36px;
    height: 36px;
    border-radius: var(--radius-full);
    box-shadow: var(--shadow-sm);
}

.theme-preview.purple {
    background: linear-gradient(135deg, #6366F1, #8B5CF6);
}

.theme-preview.ocean {
    background: linear-gradient(135deg, #0EA5E9, #06B6D4);
}

.theme-preview.forest {
    background: linear-gradient(135deg, #10B981, #059669);
}

.theme-preview.sunset {
    background: linear-gradient(135deg, #F59E0B, #EF4444);
}

.theme-preview.rose {
    background: linear-gradient(135deg, #EC4899, #F43F5E);
}

.theme-preview.midnight {
    background: linear-gradient(135deg, #475569, #1E293B);
}

.theme-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.theme-option.active .theme-label {
    color: var(--accent-primary);
}

.layout-option {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-md);
    background: transparent;
    border: 2px solid var(--glass-border);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.2s ease;
}

.layout-option:hover {
    border-color: var(--text-muted);
    background: var(--glass-bg);
}

.layout-option.active {
    border-color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.1);
}

.layout-option svg {
    width: 32px;
    height: 32px;
    color: var(--text-secondary);
}

.layout-option.active svg {
    color: var(--accent-primary);
}

.layout-option span {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.layout-option.active span {
    color: var(--accent-primary);
}

/* Marker Color Options */
.marker-options {
    display: flex;
    gap: var(--spacing-md);
}

.marker-option {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-md);
    background: transparent;
    border: 2px solid var(--glass-border);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.2s ease;
}

.marker-option:hover {
    border-color: var(--text-muted);
    background: var(--glass-bg);
}

.marker-option.active {
    border-color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.1);
}

.marker-preview {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-full);
    box-shadow: var(--shadow-sm);
}

.marker-option span {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.marker-option.active span {
    color: var(--accent-primary);
}

/* ============================================
   Theme Definitions
   ============================================ */

/* Purple (default) — dark, uses :root values */

/* Ocean — light blue */
[data-theme="ocean"] {
    --bg-primary: #EFF6FF;
    --bg-secondary: #DBEAFE;
    --bg-card: #BFDBFE;
    --bg-elevated: #93C5FD;
    --accent-primary: #2563EB;
    --accent-secondary: #3B82F6;
    --accent-pink: #0EA5E9;
    --text-primary: #1E293B;
    --text-secondary: #475569;
    --text-muted: #94A3B8;
    --gradient-primary: linear-gradient(135deg, #2563EB, #0EA5E9);
    --gradient-pink: linear-gradient(135deg, #0EA5E9, #38BDF8);
    --gradient-cyan: linear-gradient(135deg, #1D4ED8, #2563EB);
    --glass-bg: rgba(37, 99, 235, 0.06);
    --glass-border: rgba(37, 99, 235, 0.15);
    --shadow-sm: 0 2px 8px rgba(37, 99, 235, 0.1);
    --shadow-md: 0 4px 16px rgba(37, 99, 235, 0.12);
    --shadow-lg: 0 8px 32px rgba(37, 99, 235, 0.15);
    --shadow-glow: 0 0 40px rgba(37, 99, 235, 0.15);
}

/* Forest — light green */
[data-theme="forest"] {
    --bg-primary: #ECFDF5;
    --bg-secondary: #D1FAE5;
    --bg-card: #A7F3D0;
    --bg-elevated: #6EE7B7;
    --accent-primary: #059669;
    --accent-secondary: #10B981;
    --accent-pink: #047857;
    --text-primary: #1A2E23;
    --text-secondary: #3D5A4A;
    --text-muted: #6B8F7B;
    --gradient-primary: linear-gradient(135deg, #059669, #10B981);
    --gradient-pink: linear-gradient(135deg, #047857, #059669);
    --gradient-cyan: linear-gradient(135deg, #065F46, #059669);
    --glass-bg: rgba(5, 150, 105, 0.06);
    --glass-border: rgba(5, 150, 105, 0.15);
    --shadow-sm: 0 2px 8px rgba(5, 150, 105, 0.1);
    --shadow-md: 0 4px 16px rgba(5, 150, 105, 0.12);
    --shadow-lg: 0 8px 32px rgba(5, 150, 105, 0.15);
    --shadow-glow: 0 0 40px rgba(5, 150, 105, 0.15);
}

/* Sunset — warm peach/orange */
[data-theme="sunset"] {
    --bg-primary: #FFFBEB;
    --bg-secondary: #FEF3C7;
    --bg-card: #FDE68A;
    --bg-elevated: #FCD34D;
    --accent-primary: #D97706;
    --accent-secondary: #F59E0B;
    --accent-pink: #EA580C;
    --text-primary: #292524;
    --text-secondary: #57534E;
    --text-muted: #A8A29E;
    --gradient-primary: linear-gradient(135deg, #F59E0B, #EF4444);
    --gradient-pink: linear-gradient(135deg, #EA580C, #F97316);
    --gradient-cyan: linear-gradient(135deg, #D97706, #F59E0B);
    --glass-bg: rgba(217, 119, 6, 0.06);
    --glass-border: rgba(217, 119, 6, 0.15);
    --shadow-sm: 0 2px 8px rgba(217, 119, 6, 0.1);
    --shadow-md: 0 4px 16px rgba(217, 119, 6, 0.12);
    --shadow-lg: 0 8px 32px rgba(217, 119, 6, 0.15);
    --shadow-glow: 0 0 40px rgba(217, 119, 6, 0.15);
}

/* Rose — light pink */
[data-theme="rose"] {
    --bg-primary: #FFF1F2;
    --bg-secondary: #FFE4E6;
    --bg-card: #FECDD3;
    --bg-elevated: #FDA4AF;
    --accent-primary: #E11D48;
    --accent-secondary: #F43F5E;
    --accent-pink: #BE123C;
    --text-primary: #1C1017;
    --text-secondary: #4A3040;
    --text-muted: #9F7A8E;
    --gradient-primary: linear-gradient(135deg, #EC4899, #F43F5E);
    --gradient-pink: linear-gradient(135deg, #E11D48, #EC4899);
    --gradient-cyan: linear-gradient(135deg, #BE123C, #E11D48);
    --glass-bg: rgba(225, 29, 72, 0.06);
    --glass-border: rgba(225, 29, 72, 0.15);
    --shadow-sm: 0 2px 8px rgba(225, 29, 72, 0.1);
    --shadow-md: 0 4px 16px rgba(225, 29, 72, 0.12);
    --shadow-lg: 0 8px 32px rgba(225, 29, 72, 0.15);
    --shadow-glow: 0 0 40px rgba(225, 29, 72, 0.15);
}

/* Midnight — clean light gray */
[data-theme="midnight"] {
    --bg-primary: #F8FAFC;
    --bg-secondary: #F1F5F9;
    --bg-card: #E2E8F0;
    --bg-elevated: #CBD5E1;
    --accent-primary: #475569;
    --accent-secondary: #64748B;
    --accent-pink: #334155;
    --text-primary: #0F172A;
    --text-secondary: #334155;
    --text-muted: #94A3B8;
    --gradient-primary: linear-gradient(135deg, #475569, #64748B);
    --gradient-pink: linear-gradient(135deg, #334155, #475569);
    --gradient-cyan: linear-gradient(135deg, #1E293B, #475569);
    --glass-bg: rgba(71, 85, 105, 0.06);
    --glass-border: rgba(71, 85, 105, 0.15);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.1);
    --shadow-glow: 0 0 40px rgba(71, 85, 105, 0.1);
}

/* ============================================
   Mobile Responsive
   ============================================ */

@media (max-width: 768px) {
    .main-nav {
        padding: var(--spacing-sm) var(--spacing-md);
    }

    .tab-btn {
        padding: var(--spacing-sm);
        font-size: 0.65rem;
    }

    .tab-btn svg {
        width: 20px;
        height: 20px;
    }

    #capture-tab.active {
        height: calc(100vh - 100px);
        height: calc(100dvh - 100px);
    }

    .camera-area {
        max-height: 45vh;
        max-height: 45dvh;
    }

    .annotation-canvas-container {
        max-height: 45vh;
        max-height: 45dvh;
    }

    .camera-controls {
        padding: var(--spacing-sm) var(--spacing-md);
    }

    .annotation-header {
        padding: var(--spacing-sm) var(--spacing-md);
    }

    .annotation-header h3 {
        font-size: 0.85rem;
    }

    .annotation-controls {
        padding: var(--spacing-sm) var(--spacing-md);
    }

    .chat-header {
        padding: var(--spacing-sm) var(--spacing-md);
    }

    .tab-panel {
        padding: var(--spacing-md);
    }
}