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

:root {
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --card-bg: rgba(255, 255, 255, 0.95);
    --card-shadow: 0 8px 32px rgba(0,0,0,0.1);
    --border-radius: 15px;
    --transition: all 0.3s ease;
    --text-primary: #4a5568;
    --text-secondary: #718096;
    
    /* Class colors */
    --eraser-color: linear-gradient(135deg, #ff6b35 0%, #ff8c42 100%);
    --pencil-color: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --sharpener-color: linear-gradient(135deg, #7b68ee 0%, #9370db 100%);
    --ruler-color: linear-gradient(135deg, #32cd32 0%, #98fb98 100%);
    --pen-color: linear-gradient(135deg, #ff1493 0%, #ff69b4 100%);
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--primary-gradient);
    min-height: 100vh;
    padding: 10px;
    color: #333;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    
    /* Mobile optimizations */
    -webkit-user-select: none;
    -webkit-touch-callout: none;
    -webkit-tap-highlight-color: transparent;
}

.app-container {
    max-width: 1400px;
    margin: 0 auto;
}

h1 {
    text-align: center;
    color: white;
    margin-bottom: 10px;
    font-size: 2.5em;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
    font-weight: 700;
}

.subtitle {
    text-align: center;
    color: rgba(255,255,255,0.9);
    margin-bottom: 25px;
    font-size: 1.1em;
    font-weight: 400;
}

.container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    grid-template-rows: auto auto auto;
    gap: 20px;
    margin-bottom: 20px;
}

/* Enhanced Object Selection Styling */
.object-selection-section {
    grid-column: 1 / -1;
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 25px;
    box-shadow: var(--card-shadow);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.2);
}

.object-selector {
    text-align: center;
}

.object-selector > label {
    color: var(--text-primary);
    margin-bottom: 20px;
    display: block;
    font-weight: 600;
    font-size: 18px;
}

.checkbox-group {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin: 25px 0;
    flex-wrap: wrap;
}

.checkbox-item {
    position: relative;
    display: flex;
    align-items: center;
    cursor: pointer;
    user-select: none;
    transition: var(--transition);
}

.checkbox-item:hover {
    transform: translateY(-3px);
}

.checkbox-item input[type="checkbox"] {
    display: none;
}

.checkbox-item label {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 15px 25px;
    background: linear-gradient(135deg, #f7fafc 0%, #edf2f7 100%);
    border: 2px solid #e2e8f0;
    border-radius: 30px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    min-width: 160px;
    justify-content: center;
    font-size: 14px;
    text-align: center;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.class-icon {
    font-size: 16px;
    transition: transform 0.3s ease;
}

.checkbox-item:hover .class-icon {
    transform: scale(1.2);
}

/* Enhanced class-specific colors */
#eraser:checked + label {
    background: var(--eraser-color);
    color: white;
    border-color: #ff6b35;
    box-shadow: 0 6px 20px rgba(255, 107, 53, 0.4);
    transform: translateY(-2px);
}

#pencil:checked + label {
    background: var(--pencil-color);
    color: white;
    border-color: #4facfe;
    box-shadow: 0 6px 20px rgba(79, 172, 254, 0.4);
    transform: translateY(-2px);
}

#pencil-sharpener:checked + label {
    background: var(--sharpener-color);
    color: white;
    border-color: #7b68ee;
    box-shadow: 0 6px 20px rgba(123, 104, 238, 0.4);
    transform: translateY(-2px);
}

#ruler:checked + label {
    background: var(--ruler-color);
    color: white;
    border-color: #32cd32;
    box-shadow: 0 6px 20px rgba(50, 205, 50, 0.4);
    transform: translateY(-2px);
}

#pen:checked + label {
    background: var(--pen-color);
    color: white;
    border-color: #ff1493;
    box-shadow: 0 6px 20px rgba(255, 20, 147, 0.4);
    transform: translateY(-2px);
}

.checkmark {
    opacity: 0;
    transition: opacity 0.3s ease;
    font-weight: bold;
    font-size: 14px;
}

.checkbox-item input[type="checkbox"]:checked + label .checkmark {
    opacity: 1;
}

.selection-info {
    margin-top: 20px;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 15px;
    flex-wrap: wrap;
}

#selectionCount {
    color: var(--text-secondary);
    font-size: 14px;
    background: rgba(113, 128, 150, 0.1);
    padding: 12px 24px;
    border-radius: 25px;
    border: 1px solid rgba(113, 128, 150, 0.2);
    font-weight: 500;
}

.select-all-btn, .deselect-all-btn {
    padding: 8px 16px !important;
    font-size: 12px !important;
    min-width: auto !important;
    background: linear-gradient(135deg, #68d391 0%, #38a169 100%) !important;
}

.deselect-all-btn {
    background: linear-gradient(135deg, #fc8181 0%, #e53e3e 100%) !important;
}

/* Enhanced sections */
.webcam-section, .image-section {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 20px;
    box-shadow: var(--card-shadow);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.2);
}

.results-section {
    grid-column: 1 / -1;
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 25px;
    box-shadow: var(--card-shadow);
    text-align: center;
    border: 1px solid rgba(255,255,255,0.2);
}

h2 {
    color: var(--text-primary);
    margin-bottom: 20px;
    font-size: 1.3em;
    border-bottom: 2px solid #e2e8f0;
    padding-bottom: 10px;
    font-weight: 600;
}

/* Enhanced video and canvas with mobile optimization */
video, canvas {
    width: 100%;
    max-width: 100%;
    height: auto;
    border: 3px solid #e2e8f0;
    border-radius: 12px;
    display: block;
    margin: 0 auto 15px auto;
    background: #f7fafc;
    object-fit: cover;
    box-shadow: 0 6px 20px rgba(0,0,0,0.1);
    
    /* Mobile video optimizations */
    image-rendering: auto;
    image-rendering: -webkit-optimize-contrast;
    transform: translateZ(0);
    -webkit-transform: translateZ(0);
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    transition: var(--transition);
}

video {
    max-height: 70vh;
    -webkit-playsinline: true;
    -webkit-appearance: none;
    
    /* Enhanced mobile video properties */
    -webkit-user-select: none;
    user-select: none;
    -webkit-touch-callout: none;
    touch-action: manipulation;
}

canvas {
    max-height: 60vh;
    cursor: crosshair;
}

/* Enhanced controls */
.controls {
    display: flex;
    justify-content: center;
    gap: 12px;
    flex-wrap: wrap;
    margin-bottom: 15px;
}

button {
    background: var(--pencil-color);
    color: white;
    border: none;
    padding: 12px 20px;
    border-radius: 30px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 600;
    transition: var(--transition);
    min-width: 120px;
    min-height: 48px;
    touch-action: manipulation;
    -webkit-appearance: none;
    -webkit-tap-highlight-color: transparent;
    user-select: none;
    position: relative;
    overflow: hidden;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

button:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.2);
}

button:disabled {
    background: #cbd5e0;
    cursor: not-allowed;
    transform: none;
    opacity: 0.7;
    box-shadow: none;
}

button:active:not(:disabled) {
    transform: translateY(-1px);
}

/* Button variants */
#resetButton {
    background: linear-gradient(135deg, #ff6b6b 0%, #ffa500 100%);
}

#switchCameraButton {
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
}

#downloadButton {
    background: linear-gradient(135deg, #805ad5 0%, #553c9a 100%);
}

#retakeButton {
    background: linear-gradient(135deg, #38b2ac 0%, #319795 100%);
}

/* Enhanced count display */
#countDisplay {
    background: var(--primary-gradient);
    color: white;
    padding: 30px;
    border-radius: var(--border-radius);
    margin: 20px 0;
    display: inline-block;
    min-width: 250px;
    box-shadow: 0 8px 32px rgba(102, 126, 234, 0.3);
    position: relative;
    overflow: hidden;
}

#countDisplay::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(45deg, rgba(255,255,255,0.1) 0%, transparent 100%);
    pointer-events: none;
}

.count-number {
    font-size: 3em;
    font-weight: bold;
    display: block;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
    position: relative;
    z-index: 1;
}

.count-label {
    font-size: 1.1em;
    opacity: 0.9;
    margin-top: 8px;
    display: block;
    position: relative;
    z-index: 1;
}

.count-breakdown {
    font-size: 0.9em;
    margin-top: 15px;
    color: rgba(255,255,255,0.9);
    font-weight: normal;
    border-top: 1px solid rgba(255,255,255,0.3);
    padding-top: 15px;
    line-height: 1.6;
    position: relative;
    z-index: 1;
}

.confidence-info {
    font-size: 0.8em;
    margin-top: 10px;
    color: rgba(255,255,255,0.8);
    font-style: italic;
    position: relative;
    z-index: 1;
}

/* Enhanced class breakdown grid */
.class-breakdown-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 15px;
    margin: 20px 0;
}

.class-card {
    background: linear-gradient(135deg, #f7fafc 0%, #edf2f7 100%);
    border-radius: 12px;
    padding: 15px;
    text-align: center;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    transition: var(--transition);
    border: 2px solid #e2e8f0;
}

.class-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.15);
}

.class-card.active {
    border-color: #4facfe;
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    color: white;
}

.class-card-icon {
    font-size: 24px;
    margin-bottom: 8px;
    display: block;
}

.class-card-name {
    font-weight: 600;
    font-size: 12px;
    margin-bottom: 5px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.class-card-count {
    font-size: 18px;
    font-weight: bold;
}

/* Enhanced info displays */
.camera-info, .image-info {
    text-align: center;
    margin-top: 15px;
}

#cameraInfo, #imageInfo {
    font-size: 13px;
    color: #666;
    background: #f8f9fa;
    padding: 8px 16px;
    border-radius: 20px;
    display: inline-block;
    border: 1px solid #e2e8f0;
    margin-bottom: 10px;
}

.camera-capabilities {
    font-size: 11px;
    color: var(--text-secondary);
    margin-top: 5px;
}

#processingInfo {
    color: var(--text-secondary);
    font-style: italic;
    margin-top: 15px;
    font-size: 14px;
    padding: 15px;
    background: rgba(113, 128, 150, 0.1);
    border-radius: 10px;
    border-left: 4px solid #718096;
}

/* Model status indicator */
.model-status {
    margin-top: 20px;
    display: flex;
    justify-content: center;
}

.status-indicator {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 20px;
    background: rgba(113, 128, 150, 0.1);
    border-radius: 25px;
    border: 1px solid rgba(113, 128, 150, 0.2);
}

.status-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: #fbbf24;
    animation: pulse 2s infinite;
}

.status-dot.loading {
    background: #fbbf24;
}

.status-dot.ready {
    background: #10b981;
    animation: none;
}

.status-dot.error {
    background: #ef4444;
    animation: none;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

/* Performance monitor */
.performance-monitor {
    position: fixed;
    top: 10px;
    right: 10px;
    background: rgba(0,0,0,0.8);
    color: white;
    padding: 15px;
    border-radius: 10px;
    font-size: 12px;
    z-index: 1000;
    min-width: 200px;
}

.perf-stats div {
    margin: 5px 0;
    display: flex;
    justify-content: space-between;
}

/* Loading overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.8);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    backdrop-filter: blur(5px);
}

.loading-spinner {
    width: 50px;
    height: 50px;
    border: 4px solid rgba(255,255,255,0.3);
    border-top: 4px solid white;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 20px;
}

.loading-text {
    color: white;
    font-size: 18px;
    font-weight: 600;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Modal styles */
.modal {
    position: fixed;
    z-index: 10000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
    backdrop-filter: blur(5px);
}

.modal-content {
    background-color: white;
    margin: 15% auto;
    padding: 30px;
    border-radius: 15px;
    width: 90%;
    max-width: 500px;
    box-shadow: 0 10px 40px rgba(0,0,0,0.3);
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from { transform: translateY(-50px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

.close {
    color: #aaa;
    float: right;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
    line-height: 1;
}

.close:hover {
    color: #000;
}

.modal-actions {
    margin-top: 20px;
    display: flex;
    gap: 10px;
    justify-content: center;
}

/* Toast notifications */
.toast {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(0,0,0,0.8);
    color: white;
    padding: 15px 25px;
    border-radius: 25px;
    font-size: 14px;
    z-index: 1000;
    opacity: 0;
    transition: opacity 0.3s ease;
    backdrop-filter: blur(10px);
}

.toast.show {
    opacity: 1;
}

/* High DPI display optimization */
@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
    video, canvas {
        image-rendering: -webkit-optimize-contrast;
        image-rendering: crisp-edges;
    }
}

/* Mobile Responsive Design */
@media (max-width: 768px) {
    body {
        padding: 8px;
    }

    .container {
        grid-template-columns: 1fr;
        gap: 15px;
    }

    h1 {
        font-size: 2em;
        margin-bottom: 8px;
    }

    .subtitle {
        font-size: 1em;
        margin-bottom: 20px;
    }

    .object-selection-section,
    .webcam-section,
    .image-section {
        padding: 18px;
    }

    .checkbox-group {
        flex-direction: column;
        align-items: center;
        gap: 12px;
        margin: 20px 0;
    }
    
    .checkbox-item label {
        min-width: 220px;
        padding: 16px 28px;
        font-size: 15px;
    }

    .selection-info {
        flex-direction: column;
        gap: 10px;
    }

    .controls {
        flex-direction: column;
        align-items: center;
        gap: 10px;
    }

    button {
        width: 100%;
        max-width: 280px;
        padding: 16px 20px;
        font-size: 15px;
        min-height: 52px;
    }

    video {
        max-height: 60vh;
    }

    canvas {
        max-height: 50vh;
    }

    #countDisplay {
        padding: 25px;
        min-width: 200px;
        max-width: 90%;
    }

    .count-number {
        font-size: 2.2em;
    }

    .class-breakdown-grid {
        grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
        gap: 10px;
    }

    .performance-monitor {
        position: relative;
        top: auto;
        right: auto;
        margin: 20px 0;
        background: rgba(113, 128, 150, 0.1);
        color: var(--text-secondary);
    }
}

/* Small mobile devices */
@media (max-width: 480px) {
    .app-container {
        padding: 0 5px;
    }

    h1 {
        font-size: 1.6em;
        margin-bottom: 5px;
    }

    .subtitle {
        font-size: 0.9em;
    }

    .object-selection-section {
        padding: 15px;
    }

    .checkbox-item label {
        min-width: 200px;
        padding: 14px 24px;
        font-size: 14px;
    }

    button {
        font-size: 14px;
        min-height: 48px;
        max-width: 250px;
    }

    video, canvas {
        max-height: 45vh;
    }

    .modal-content {
        margin: 10% auto;
        padding: 20px;
        width: 95%;
    }
}

/* Tablet landscape optimization */
@media (min-width: 769px) and (max-width: 1024px) and (orientation: landscape) {
    .container {
        grid-template-columns: 1fr 1fr;
    }
    
    .checkbox-group {
        justify-content: center;
        gap: 12px;
    }
    
    .checkbox-item label {
        min-width: 140px;
        padding: 12px 20px;
        font-size: 13px;
    }

    video, canvas {
        max-height: 50vh;
    }
}

/* Large screens */
@media (min-width: 1200px) {
    .container {
        max-width: 1400px;
        gap: 25px;
    }
    
    .object-selection-section {
        padding: 30px;
    }
    
    .checkbox-group {
        gap: 20px;
    }
    
    .checkbox-item label {
        min-width: 170px;
        padding: 16px 28px;
        font-size: 15px;
    }

    video {
        max-height: 75vh;
    }

    canvas {
        max-height: 65vh;
    }
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
    :root {
        --card-bg: rgba(45, 55, 72, 0.95);
        --text-primary: #e2e8f0;
        --text-secondary: #cbd5e0;
    }

    body {
        background: linear-gradient(135deg, #2d3748 0%, #4a5568 100%);
    }

    .object-selection-section,
    .webcam-section, 
    .image-section, 
    .results-section {
        background: var(--card-bg);
        color: var(--text-primary);
        border: 1px solid rgba(255,255,255,0.1);
    }

    h2 {
        color: var(--text-primary);
        border-bottom-color: #4a5568;
    }

    .checkbox-item label {
        background: linear-gradient(135deg, #4a5568 0%, #2d3748 100%);
        color: var(--text-primary);
        border-color: #4a5568;
    }

    .class-card {
        background: linear-gradient(135deg, #4a5568 0%, #2d3748 100%);
        color: var(--text-primary);
        border-color: #4a5568;
    }

    #selectionCount {
        background: rgba(113, 128, 150, 0.3);
        color: var(--text-secondary);
        border-color: #4a5568;
    }

    #processingInfo {
        background: rgba(113, 128, 150, 0.2);
        color: var(--text-secondary);
        border-left-color: var(--text-secondary);
    }

    #cameraInfo, #imageInfo {
        background: rgba(45, 55, 72, 0.8);
        color: var(--text-secondary);
        border-color: #4a5568;
    }

    video, canvas {
        border-color: #4a5568;
        background: #2d3748;
    }

    .modal-content {
        background-color: #2d3748;
        color: var(--text-primary);
    }
}

/* Print styles */
@media print {
    body {
        background: white;
        color: black;
    }
    
    .webcam-section, .controls, .performance-monitor {
        display: none;
    }
    
    .object-selection-section,
    .image-section,
    .results-section {
        background: white;
        box-shadow: none;
        border: 1px solid #ccc;
        break-inside: avoid;
    }
}

/* Accessibility enhancements */
@media (prefers-contrast: high) {
    .checkbox-item label {
        border-width: 3px;
    }
    
    button {
        border: 2px solid #000;
    }
    
    #countDisplay {
        border: 3px solid #000;
    }
}

@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    .checkbox-item:hover,
    button:hover:not(:disabled) {
        transform: none;
    }
    
    .loading-spinner {
        animation: none;
        border: 4px solid #ccc;
        border-top: 4px solid #333;
    }
}

/* Focus styles for accessibility */
button:focus,
.checkbox-item input:focus + label {
    outline: 3px solid #4facfe;
    outline-offset: 2px;
}

/* Touch device optimizations */
@media (hover: none) and (pointer: coarse) {
    .checkbox-item:hover {
        transform: none;
    }
    
    button:hover:not(:disabled) {
        transform: none;
        box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    }
}