/* =========================================
   ECG Virtual Lab — Clinical Design Stylesheet
   ========================================= */

/* --- CSS Variables / Theme --- */
:root {
    /* Light clinical theme */
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-sidebar: #f1f5f9;
    --bg-card: #ffffff;
    --bg-card-hover: #f8fafc;
    
    /* Accent colors - soft clinical blue */
    --accent: #4a90a4;
    --accent-light: #e0f2f7;
    --accent-dark: #2d6a7a;
    --accent-border: #a8d4e6;
    
    /* Status colors */
    --success: #10b981;
    --success-light: #d1fae5;
    --warning: #f59e0b;
    --warning-light: #fef3c7;
    --danger: #ef4444;
    --danger-light: #fee2e2;
    
    /* Text colors */
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    
    /* Border colors */
    --border: #e2e8f0;
    --border-light: #f1f5f9;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1), 0 1px 2px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    
    /* Radius */
    --radius: 8px;
    --radius-sm: 6px;
    --radius-lg: 12px;
    
    /* Transitions */
    --transition: all 0.2s ease;
    --transition-slow: all 0.3s ease;
    
    /* Typography */
    --font-sans: 'Inter', 'Segoe UI', system-ui, -apple-system, sans-serif;
    --font-mono: 'Fira Code', 'Consolas', monospace;
}

/* --- Reset & Base --- */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
    font-size: 15px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    -webkit-tap-highlight-color: transparent;
}

/* Touch-friendly tap targets */
button, 
.btn-primary, 
.nav-step, 
.equipment-item,
.condition-card,
.analysis-tab {
    -webkit-tap-highlight-color: transparent;
    touch-action: manipulation;
}

.hidden {
    display: none !important;
}

/* --- SVG & Canvas Base Styles --- */
svg {
    display: block;
    max-width: 100%;
    height: auto;
}

canvas {
    display: block;
    max-width: 100%;
}

/* --- Loading Screen --- */
#loading-screen {
    position: fixed;
    inset: 0;
    background: linear-gradient(135deg, #f8fafc 0%, #e0f2f7 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    transition: opacity 0.5s ease;
}

#loading-screen.fade-out {
    opacity: 0;
    pointer-events: none;
}

.loader-content {
    text-align: center;
}

.loader-spinner {
    width: 60px;
    height: 60px;
    margin: 0 auto 24px;
}

.spinner-svg {
    animation: rotate 1.5s linear infinite;
}

.spinner-circle {
    animation: dash 1.5s ease-in-out infinite;
}

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

@keyframes dash {
    0% { stroke-dashoffset: 100; }
    50% { stroke-dashoffset: 30; }
    100% { stroke-dashoffset: 100; }
}

.loader-content h1 {
    font-size: 1.75rem;
    color: var(--accent-dark);
    margin-bottom: 8px;
    font-weight: 600;
}

.loader-content p {
    color: var(--text-secondary);
    margin-bottom: 24px;
    font-size: 0.95rem;
}

.load-bar {
    width: 240px;
    height: 4px;
    background: var(--border);
    border-radius: 4px;
    margin: 0 auto;
    overflow: hidden;
}

.load-fill {
    width: 0;
    height: 100%;
    background: linear-gradient(90deg, var(--accent), var(--accent-dark));
    border-radius: 4px;
    transition: width 0.3s ease;
}

/* --- App Layout --- */
#app {
    min-height: 100vh;
    width: 100%;
}

/* --- Left Sidebar Navigation --- */
#sidebar-nav {
    background: var(--bg-sidebar);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    position: fixed;
    left: 0;
    top: 0;
    bottom: 0;
    width: 280px;
    z-index: 100;
}

.sidebar-header {
    padding: 24px 20px;
    border-bottom: 1px solid var(--border);
    text-align: center;
}

.sidebar-logo {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 12px;
}

.logo-image {
    max-width: 100%;
    max-height: 60px;
    object-fit: contain;
    border-radius: var(--radius);
}

.lab-title {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    margin-bottom: 4px;
}

.lab-icon {
    font-size: 1.2rem;
    color: var(--accent);
}

.sidebar-header h2 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.lab-subtitle {
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* Vertical Navigation Steps */
.nav-steps-vertical {
    flex: 1;
    padding: 8px;
    overflow-y: auto;
}

.nav-step {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    border-radius: var(--radius);
    cursor: pointer;
    transition: var(--transition);
    margin-bottom: 4px;
    position: relative;
}

.nav-step:hover {
    background: var(--bg-card);
}

.nav-step.active {
    background: var(--accent-light);
    border: 1px solid var(--accent-border);
}

.nav-step.completed {
    background: var(--success-light);
    border: 1px solid #a7f3d0;
}

.step-indicator {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--bg-card);
    border: 2px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    position: relative;
}

.nav-step.active .step-indicator {
    background: var(--accent);
    border-color: var(--accent);
    color: white;
}

.nav-step.completed .step-indicator {
    background: var(--success);
    border-color: var(--success);
    color: white;
}

.step-indicator i {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.nav-step.active .step-indicator i,
.nav-step.completed .step-indicator i {
    color: white;
}

.step-check {
    display: none;
    position: absolute;
    top: -4px;
    right: -4px;
    width: 16px;
    height: 16px;
    background: var(--success);
    border-radius: 50%;
    align-items: center;
    justify-content: center;
}

.nav-step.completed .step-check {
    display: flex;
}

.step-check i {
    font-size: 0.6rem;
    color: white;
}

.step-content {
    display: flex;
    flex-direction: column;
}

.step-label {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-primary);
}

/* Sidebar Footer */
.sidebar-footer {
    padding: 16px;
    border-top: 1px solid var(--border);
}

.btn-glossary {
    width: 100%;
    padding: 10px 16px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 0.875rem;
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: var(--transition);
}

.btn-glossary:hover {
    background: var(--bg-card-hover);
    color: var(--text-primary);
}

/* --- Main Content Area --- */
#main-content {
    margin-left: 280px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Top-right reset control */
.lab-reset-btn {
    position: fixed;
    top: 16px;
    right: 18px;
    z-index: 1200;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 9px 14px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: var(--bg-card);
    color: var(--text-secondary);
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.lab-reset-btn:hover {
    border-color: #fca5a5;
    color: #b91c1c;
    background: #fff7f7;
    box-shadow: var(--shadow);
}

.lab-reset-btn:active {
    transform: translateY(1px);
}

/* Navigation Buttons */
.nav-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 18px;
    border: 1px solid var(--border);
    background: var(--bg-card);
    color: var(--text-secondary);
    border-radius: var(--radius);
    cursor: pointer;
    font-size: 0.875rem;
    font-weight: 500;
    transition: var(--transition);
}

.nav-btn:hover:not(:disabled) {
    background: var(--bg-card-hover);
    color: var(--text-primary);
    border-color: var(--accent-border);
}

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

.nav-btn.nav-next {
    background: var(--accent);
    border-color: var(--accent);
    color: white;
}

.nav-btn.nav-next:hover:not(:disabled) {
    background: var(--accent-dark);
    border-color: var(--accent-dark);
}

/* --- Lab Steps --- */
.lab-step {
    display: none;
    padding: 24px;
    flex: 1;
    width: 100%;
}

.lab-step.active {
    display: block;
}

.step-container {
    max-width: 100%;
    width: 100%;
    margin: 0;
}

/* Section Headers */
.section-header {
    display: flex;
    align-items: flex-start;
    gap: 16px;
    margin-bottom: 32px;
    padding-bottom: 24px;
    border-bottom: 1px solid var(--border);
}

.section-header i {
    width: 48px;
    height: 48px;
    background: var(--accent-light);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    color: var(--accent);
    flex-shrink: 0;
}

.section-header h2 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.section-header p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* --- Welcome / Start Step --- */
.welcome-card {
    text-align: center;
    padding: 48px 32px;
    margin-bottom: 32px;
}

.welcome-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--accent-light) 0%, #ffffff 100%);
    border: 1px solid var(--accent-border);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 24px;
}

.welcome-icon i {
    font-size: 2rem;
    color: var(--accent);
}

.welcome-card h2 {
    font-size: 1.85rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 10px;
    letter-spacing: -0.02em;
}

.welcome-subtitle {
    color: var(--text-secondary);
    font-size: 1.05rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

/* Info Grid */
.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
    margin-bottom: 32px;
}

.info-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 28px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.info-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--accent) 0%, var(--accent-dark) 100%);
    opacity: 0;
    transition: var(--transition);
}

.info-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent-border);
}

.info-card:hover::before {
    opacity: 1;
}

.info-card-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border);
}

.info-card-header i {
    width: 44px;
    height: 44px;
    background: linear-gradient(135deg, var(--accent-light) 0%, #ffffff 100%);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    color: var(--accent);
    box-shadow: 0 2px 8px rgba(74, 144, 164, 0.15);
    transition: var(--transition);
}

.info-card:hover .info-card-header i {
    transform: scale(1.1);
    box-shadow: 0 4px 12px rgba(74, 144, 164, 0.25);
}

.info-card-header h3 {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

.info-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
}

.info-card ul {
    list-style: none;
    padding: 0;
}

.info-card ul li {
    padding: 8px 0;
    padding-left: 20px;
    position: relative;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.info-card ul li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 8px;
    height: 8px;
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent-dark) 100%);
    border-radius: 50%;
    box-shadow: 0 0 0 3px var(--accent-light);
}

/* Science Section Card */
.science-section-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 32px;
    margin-bottom: 32px;
    box-shadow: var(--shadow);
    position: relative;
}

.science-section-card::after {
    content: '';
    position: absolute;
    top: 20px;
    right: 20px;
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--accent-light) 0%, transparent 100%);
    border-radius: 50%;
    opacity: 0.5;
    pointer-events: none;
}

.science-section-card > h3 {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 28px;
    padding-bottom: 18px;
    border-bottom: 2px solid var(--border);
    letter-spacing: -0.01em;
}

.science-section-card > h3 i {
    color: var(--accent);
    font-size: 1.3rem;
}

.science-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
}

.science-item {
    padding: 24px;
    background: linear-gradient(145deg, var(--bg-primary) 0%, #ffffff 100%);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.science-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: linear-gradient(180deg, var(--accent) 0%, var(--accent-dark) 100%);
    opacity: 0;
    transition: var(--transition);
}

.science-item:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
    border-color: var(--accent-border);
}

.science-item:hover::before {
    opacity: 1;
}

.science-item h4 {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 14px;
    letter-spacing: -0.01em;
}

.science-item h4 i {
    color: var(--accent);
    font-size: 1rem;
    width: 32px;
    height: 32px;
    background: var(--accent-light);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.science-item:hover h4 i {
    background: var(--accent);
    color: white;
}

.science-item p {
    color: var(--text-secondary);
    font-size: 0.85rem;
    line-height: 1.6;
}

.science-item ul.signal-specs {
    list-style: none;
    padding: 0;
    margin: 0;
}

.science-item ul.signal-specs li {
    padding: 8px 0;
    font-size: 0.9rem;
    color: var(--text-secondary);
    border-bottom: 1px dashed var(--border-light);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.science-item ul.signal-specs li:last-child {
    border-bottom: none;
}

.science-item ul.signal-specs li strong {
    color: var(--text-primary);
    font-weight: 600;
}

/* ECG Complex Visualization */
.ecg-preview-visualization {
    background: linear-gradient(180deg, var(--bg-card) 0%, var(--bg-primary) 100%);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 28px;
    margin-bottom: 32px;
    text-align: center;
    box-shadow: var(--shadow);
    position: relative;
    overflow: hidden;
}

.ecg-preview-visualization::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, var(--accent-light) 0%, transparent 60%);
    opacity: 0.3;
    pointer-events: none;
}

.ecg-preview-visualization canvas {
    max-width: 100%;
    height: auto;
    border-radius: var(--radius-lg);
    background: linear-gradient(180deg, #1a2332 0%, #0f1419 100%);
    border: 2px solid var(--border);
    box-shadow: var(--shadow-md), inset 0 0 60px rgba(0,0,0,0.3);
    position: relative;
    z-index: 1;
}

.canvas-caption {
    margin-top: 16px;
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 500;
    position: relative;
    z-index: 1;
}

/* Primary Button */
.btn-primary {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    padding: 14px 28px;
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent-dark) 100%);
    color: white;
    border: none;
    border-radius: var(--radius-lg);
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 4px 14px rgba(74, 144, 164, 0.35);
    position: relative;
    overflow: hidden;
}

.btn-primary::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    transition: 0.5s;
}

.btn-primary:hover::before {
    left: 100%;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(74, 144, 164, 0.45);
}

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

.btn-primary.btn-lg {
    padding: 18px 42px;
    font-size: 1.05rem;
    border-radius: 50px;
}

/* --- Equipment Step --- */
.equipment-lab {
    display: grid;
    grid-template-columns: minmax(300px, 400px) 1fr;
    gap: 32px;
    width: 100%;
}

.equipment-bench {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
}

.equipment-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 20px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
}

.equipment-item:hover {
    border-color: var(--accent-border);
    box-shadow: var(--shadow);
}

.equipment-item.explored {
    border-color: var(--success);
    background: var(--success-light);
}

.equip-visual {
    width: 64px;
    height: 64px;
    margin: 0 auto 12px;
    background: var(--accent-light);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
}

.equip-visual i {
    font-size: 1.5rem;
    color: var(--accent);
}

.equipment-item.explored .equip-visual {
    background: var(--success-light);
}

.equipment-item.explored .equip-visual i {
    color: var(--success);
}

.equip-label {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-primary);
    display: block;
}

.equip-check {
    position: absolute;
    top: 8px;
    right: 8px;
    width: 24px;
    height: 24px;
    background: var(--success);
    border-radius: 50%;
    display: none;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 0.75rem;
}

.equipment-item.explored .equip-check {
    display: flex;
}

/* Equipment Info Panel */
.equipment-info-panel {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
    min-height: 400px;
}

.info-placeholder {
    text-align: center;
    padding: 48px 24px;
    color: var(--text-muted);
}

.info-placeholder i {
    font-size: 2.5rem;
    margin-bottom: 16px;
    color: var(--border);
}

.info-placeholder p {
    font-size: 0.9rem;
}

.info-details h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 16px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border);
}

#equip-detail-body {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

#equip-detail-body p {
    margin-bottom: 12px;
}

#equip-detail-body strong {
    color: var(--text-primary);
}

/* Step Progress */
.step-progress {
    margin-top: 24px;
    display: flex;
    align-items: center;
    gap: 16px;
    flex-wrap: wrap;
}

.progress-bar {
    flex: 1;
    height: 6px;
    background: var(--border);
    border-radius: 3px;
    min-width: 200px;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent) 0%, var(--success) 100%);
    border-radius: 3px;
    transition: width 0.3s ease;
    width: 0%;
}

.progress-text {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
}

/* --- Panel Header --- */
.panel-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 20px;
}

.panel-header i {
    width: 32px;
    height: 32px;
    background: var(--accent-light);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent);
    font-size: 0.9rem;
}

.panel-header h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

/* --- Muscle Selection Panel --- */
.muscle-selection-panel {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
    margin-bottom: 24px;
}

.muscle-instruction {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 20px;
}

.body-muscle-container {
    display: grid;
    grid-template-columns: minmax(280px, 1fr) 1.5fr;
    gap: 32px;
}

.body-diagram {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
}

.body-svg {
    width: 100%;
    height: auto;
    min-height: 400px;
}

.body-head, .body-neck, .body-torso, .body-arm, .body-leg, .body-hand, .body-foot {
    fill: #cbd5e1;
    stroke: #94a3b8;
    stroke-width: 1.5;
}

.muscle-region {
    fill: #bfdbfe;
    stroke: #3b82f6;
    stroke-width: 2;
    cursor: pointer;
    transition: var(--transition);
    opacity: 0.8;
}

.muscle-region:hover {
    opacity: 1;
    fill: #60a5fa;
}

.muscle-region.selected {
    fill: var(--accent);
    opacity: 1;
}

.muscle-info-card {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
}

.muscle-placeholder {
    text-align: center;
    padding: 40px 20px;
    color: var(--text-muted);
}

.muscle-placeholder i, .big-icon {
    font-size: 2rem;
    margin-bottom: 12px;
    color: var(--border);
    display: block;
}

#selected-muscle-name {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 16px;
}

#muscle-info-text {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

#muscle-info-text p {
    margin-bottom: 10px;
}

#select-muscle-btn {
    margin-top: 20px;
    width: 100%;
}

/* --- Prep Workspace --- */
.prep-workspace {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
}

.selected-muscle-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 20px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border);
    font-size: 0.95rem;
}

.selected-muscle-header strong {
    color: var(--accent);
}

.btn-small {
    padding: 6px 12px;
    font-size: 0.8rem;
    border-radius: var(--radius-sm);
}

.btn-secondary {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
}

.btn-secondary:hover {
    border-color: var(--accent-border);
    color: var(--text-primary);
}

/* Arm Container / Prep Diagram */
.arm-container {
    display: flex;
    justify-content: center;
    margin-bottom: 24px;
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
}

.arm-svg {
    width: 100%;
    max-width: 560px;
    height: auto;
    min-height: 350px;
    display: block;
    margin: 0 auto;
}

.arm-skin {
    fill: #f5e6d3;
    stroke: #d4c4b0;
    stroke-width: 2;
}

.prep-zone {
    fill: rgba(59, 130, 246, 0.15);
    stroke: #3b82f6;
    stroke-width: 2;
    stroke-dasharray: 5 5;
    cursor: pointer;
    pointer-events: all;
    transition: var(--transition);
}

.prep-zone.cleaned {
    stroke: #10b981;
    stroke-dasharray: none;
}

.prep-zone.abraded {
    fill: rgba(16, 185, 129, 0.1);
}

.prep-zone.gelled {
    fill: rgba(16, 185, 129, 0.2);
}

.prep-zone.electrode-placed {
    fill: #10b981;
    opacity: 0.3;
}

.prep-zone.wrong-target {
    stroke: var(--danger);
    fill: rgba(239, 68, 68, 0.2);
    animation: wrongDropPulse 0.35s ease-in-out 2;
}

@keyframes wrongDropPulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.08); }
    100% { transform: scale(1); }
}

.electrode-target {
    fill: #bfdbfe;
    stroke: #3b82f6;
    stroke-width: 2;
}

.zone-label {
    font-size: 12px;
    fill: var(--text-secondary);
}

.zone-label-name {
    font-weight: 600;
    fill: var(--text-primary);
}

.zone-label-bold,
.arm-svg text {
    pointer-events: none;
    user-select: none;
}

/* Prep Tools */

/* Horizontal Progress Bar */
.prep-progress-bar {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0;
    margin-bottom: 24px;
    padding: 16px 24px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
}

.prep-step-indicator {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    transition: var(--transition);
}

.prep-step-indicator .step-circle {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--bg-primary);
    border: 2px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.prep-step-indicator .step-circle i {
    font-size: 1rem;
    color: var(--text-muted);
    transition: var(--transition);
}

.prep-step-indicator .step-name {
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-muted);
    transition: var(--transition);
}

.prep-step-indicator.active .step-circle {
    background: var(--accent);
    border-color: var(--accent);
    box-shadow: 0 0 0 4px var(--accent-light);
}

.prep-step-indicator.active .step-circle i {
    color: white;
}

.prep-step-indicator.active .step-name {
    color: var(--accent);
    font-weight: 600;
}

.prep-step-indicator.completed .step-circle {
    background: var(--success);
    border-color: var(--success);
}

.prep-step-indicator.completed .step-circle i {
    color: white;
}

.prep-step-indicator.completed .step-name {
    color: var(--success);
}

.step-connector {
    width: 60px;
    height: 3px;
    background: var(--border);
    margin: 0 8px;
    margin-bottom: 24px;
    border-radius: 2px;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.step-connector::after {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 0;
    background: var(--success);
    transition: width 0.5s ease;
}

.step-connector.filled::after {
    width: 100%;
}

/* Floating Impedance Indicator */
.floating-impedance {
    position: fixed;
    top: 100px;
    right: 24px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 16px;
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: 16px;
    z-index: 100;
    opacity: 0;
    transform: translateX(20px);
    transition: all 0.3s ease;
    pointer-events: none;
}

.floating-impedance.visible {
    opacity: 1;
    transform: translateX(0);
    pointer-events: auto;
}

.impedance-ring {
    position: relative;
    width: 70px;
    height: 70px;
}

.imp-ring-svg {
    width: 100%;
    height: 100%;
    transform: rotate(-90deg);
}

.imp-ring-bg {
    fill: none;
    stroke: var(--border);
    stroke-width: 6;
}

.imp-ring-fill {
    fill: none;
    stroke: var(--accent);
    stroke-width: 6;
    stroke-linecap: round;
    stroke-dasharray: 220;
    stroke-dashoffset: 220;
    transition: stroke-dashoffset 0.5s ease, stroke 0.3s ease;
}

.imp-ring-fill.good {
    stroke: var(--success);
}

.imp-ring-fill.warning {
    stroke: var(--warning);
}

.imp-ring-fill.bad {
    stroke: var(--danger);
}

.imp-value-center {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 0.9rem;
    font-weight: 700;
    color: var(--text-primary);
}

.impedance-info {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.impedance-info .imp-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.impedance-info .imp-status {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.impedance-info .imp-status.good { color: var(--success); }
.impedance-info .imp-status.warning { color: var(--warning); }
.impedance-info .imp-status.bad { color: var(--danger); }

/* Main Prep Area Layout */
.prep-main-area {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
    align-items: start;
}

.prep-tools h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 16px;
}

.prep-instruction-banner {
    display: flex;
    align-items: center;
    gap: 10px;
    background: var(--accent-light);
    border: 1px solid var(--accent-border);
    border-radius: var(--radius);
    padding: 12px 16px;
    margin-bottom: 20px;
}

.banner-icon {
    color: var(--accent);
    font-size: 1.1rem;
}

.banner-text {
    font-size: 0.875rem;
    color: var(--accent-dark);
}

.tool-steps {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.tool-step {
    display: flex;
    gap: 16px;
    padding: 16px;
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    opacity: 0.6;
    transition: var(--transition);
}

.tool-step.active {
    opacity: 1;
    border-color: var(--accent-border);
    background: var(--accent-light);
}

.tool-step.completed {
    opacity: 1;
    border-color: var(--success);
    background: var(--success-light);
}

.tool-icon {
    width: 60px;
    height: 60px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: grab;
}

.tool-emoji {
    font-size: 1.5rem;
}

.step-info {
    flex: 1;
}

.step-info strong {
    display: block;
    font-size: 0.95rem;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.step-desc {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.substep-tracker {
    display: flex;
    gap: 16px;
}

.substep-item {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.8rem;
    color: var(--text-muted);
}

.substep-item .dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--border);
    transition: var(--transition);
}

.substep-item .dot.done {
    background: var(--success);
}

/* Electrode Tray */
.electrode-tray-container {
    display: flex;
    gap: 8px;
    width: auto;
    height: auto;
    padding: 8px;
}

.electrode-pick-wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
}

.electrode-pick {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--accent);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: grab;
    transition: var(--transition);
}

.electrode-pick.placed {
    background: var(--success);
}

.e-symbol {
    font-size: 0.7rem;
    font-weight: 600;
    color: white;
}

.electrode-label {
    font-size: 0.7rem;
    color: var(--text-muted);
}

.electrode-placement-guide {
    display: flex;
    gap: 16px;
    margin-bottom: 12px;
}

.guide-item {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.guide-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

.guide-dot.e1 { background: #4a90a4; }
.guide-dot.e2 { background: #10b981; }
.guide-dot.e3 { background: #ff9800; }
.guide-dot.e4 { background: #e11d48; }
.guide-dot.gnd { background: #64748b; }

.substep-progress {
    display: flex;
    gap: 8px;
}

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

/* Collapsible Step Cards */
.collapsible-step {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    margin-bottom: 12px;
    transition: var(--transition);
    opacity: 0.6;
}

.collapsible-step.active {
    opacity: 1;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-light);
}

.collapsible-step.completed {
    opacity: 1;
    border-color: var(--success);
}

.collapsible-step.completed .step-header {
    background: var(--success-light);
}

.step-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 16px;
    background: var(--bg-primary);
    cursor: pointer;
    transition: var(--transition);
}

.step-header:hover {
    background: var(--bg-card-hover);
}

.step-header-left {
    display: flex;
    align-items: center;
    gap: 12px;
}

.step-header-left .tool-icon {
    width: 44px;
    height: 44px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: grab;
    flex-shrink: 0;
}

.step-header-left .tool-emoji {
    font-size: 1.25rem;
}

.step-title {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.step-title strong {
    font-size: 0.9rem;
    color: var(--text-primary);
}

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

.step-header-right {
    display: flex;
    align-items: center;
    gap: 12px;
}

.site-dots {
    display: flex;
    gap: 6px;
}

.site-dots .dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--border);
    transition: var(--transition);
}

.site-dots .dot.done {
    background: var(--success);
}

.collapse-icon {
    color: var(--text-muted);
    font-size: 0.8rem;
    transition: transform 0.3s ease;
}

.collapsible-step.active .collapse-icon {
    transform: rotate(180deg);
}

.collapsible-step:not(.active) .step-body {
    display: none;
}

.step-body {
    padding: 16px;
    border-top: 1px solid var(--border);
    animation: slideDown 0.3s ease;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.step-instruction {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 16px;
}

.step-body .substep-tracker {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
}

.step-body .substep-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.8rem;
    color: var(--text-muted);
}

.substep-dot {
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--border);
    transition: var(--transition);
}

.substep-item.done .substep-dot {
    background: var(--success);
}

/* Electrode Tray in Collapsible */
.electrode-tray {
    display: flex;
    gap: 6px;
    padding: 6px;
    background: var(--bg-primary);
    border-radius: var(--radius);
    flex-wrap: wrap;
    max-width: 280px;
}

.electrode-tray .electrode-pick {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    background: var(--accent);
    color: white;
    font-size: 0.65rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: grab;
    transition: var(--transition);
}

.electrode-tray .electrode-pick.selected {
    background: var(--accent-dark);
    box-shadow: 0 0 0 3px var(--accent-light);
    transform: scale(1.08);
}

.electrode-tray .electrode-pick.placed {
    background: var(--success);
    opacity: 0.5;
    cursor: default;
}

#electrode-thread-layer .electrode-thread {
    stroke: #334155;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-dasharray: 4 3;
    opacity: 0.85;
}

.electrode-guide {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

/* ===== VALIDATION PANEL ===== */
.validation-panel {
    background: var(--bg-card);
    border: 2px solid var(--accent-border);
    border-radius: var(--radius-lg);
    padding: 24px;
    margin: 24px 0;
    transition: var(--transition);
}

.validation-panel.hidden {
    display: none;
}

.validation-header {
    display: flex;
    align-items: flex-start;
    gap: 16px;
    margin-bottom: 24px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border);
}

.validation-header i {
    width: 40px;
    height: 40px;
    background: var(--success-light);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--success);
    font-size: 1.1rem;
    flex-shrink: 0;
}

.validation-header h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.validation-header p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin: 4px 0 0 0;
}

.validation-checks {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 16px;
    margin-bottom: 24px;
}

.validation-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px;
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    transition: var(--transition);
}

.validation-item.correct {
    background: var(--success-light);
    border-color: var(--success);
}

.validation-item.incorrect {
    background: var(--danger-light);
    border-color: var(--danger);
}

.validate-icon {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    font-size: 0.8rem;
    color: var(--text-muted);
}

.validation-item.correct .validate-icon {
    color: var(--success);
}

.validation-item.incorrect .validate-icon {
    color: var(--danger);
}

.validate-label {
    display: flex;
    flex-direction: column;
    gap: 4px;
    flex: 1;
}

.validate-label strong {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.95rem;
}

.validate-details {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.validate-status {
    display: none;
}

.validate-status.visible {
    display: flex;
    align-items: center;
}

.status-correct,
.status-incorrect {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.85rem;
    font-weight: 500;
}

.status-correct {
    color: var(--success);
}

.status-incorrect {
    color: var(--danger);
    display: none;
}

.status-incorrect.visible {
    display: flex;
}

.validation-summary {
    background: var(--accent-light);
    border: 1px solid var(--accent-border);
    border-radius: var(--radius);
    padding: 16px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
}

.summary-score {
    display: flex;
    align-items: baseline;
    gap: 8px;
}

.score-label {
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.95rem;
}

.score-value {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--accent);
}

.summary-message {
    text-align: right;
    flex: 1;
}

.summary-message p {
    margin: 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* ===== MICRO-ANIMATIONS ===== */

/* Skin Shine Layer (after cleaning) */
.skin-shine-layer {
    fill: transparent;
    opacity: 0;
    transition: all 0.8s ease;
    pointer-events: none;
}

.arm-svg.cleaned .skin-shine-layer {
    fill: url(#shine-gradient);
    opacity: 0.4;
    animation: shineEffect 2s ease-in-out infinite;
}

@keyframes shineEffect {
    0%, 100% { opacity: 0.3; }
    50% { opacity: 0.5; }
}

/* Skin Texture Layer (after abrasion) */
.skin-texture-layer {
    fill: transparent;
    opacity: 0;
    pointer-events: none;
    transition: all 0.5s ease;
}

.arm-svg.abraded .skin-texture-layer {
    fill: url(#abraded-texture);
    opacity: 0.6;
}

/* Cleaned Zone Shine */
.prep-zone.cleaned {
    stroke: #10b981;
    stroke-dasharray: none;
    animation: cleanedPulse 1.5s ease-out;
}

@keyframes cleanedPulse {
    0% {
        filter: drop-shadow(0 0 8px rgba(16, 185, 129, 0.8));
    }
    100% {
        filter: drop-shadow(0 0 0 transparent);
    }
}

/* Abraded Zone Texture */
.prep-zone.abraded {
    fill: rgba(239, 68, 68, 0.15);
    animation: abradedEffect 0.3s ease;
}

@keyframes abradedEffect {
    0%, 33%, 66% { transform: translateX(-1px); }
    16%, 50%, 83% { transform: translateX(1px); }
    100% { transform: translateX(0); }
}

/* Gel Shine Spots */
.gel-shine {
    fill: transparent;
    opacity: 0;
    pointer-events: none;
    transition: all 0.5s ease;
}

.gel-shine.visible {
    fill: rgba(59, 130, 246, 0.3);
    opacity: 1;
    animation: gelShimmer 2s ease-in-out infinite;
}

@keyframes gelShimmer {
    0%, 100% {
        fill: rgba(59, 130, 246, 0.25);
        transform: scale(1);
    }
    50% {
        fill: rgba(59, 130, 246, 0.4);
        transform: scale(1.05);
    }
}

/* Gelled Zone Effect */
.prep-zone.gelled {
    fill: rgba(59, 130, 246, 0.3);
    filter: drop-shadow(0 0 6px rgba(59, 130, 246, 0.5));
}

/* Placed Electrodes */
.placed-electrode {
    opacity: 0;
    transform: scale(0.5);
    transition: all 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.placed-electrode.visible {
    opacity: 1;
    transform: scale(1);
}

.electrode-body {
    fill: var(--accent);
    stroke: white;
    stroke-width: 2;
}

.electrode-text {
    fill: white;
    font-size: 10px;
    font-weight: 600;
    text-anchor: middle;
    dominant-baseline: middle;
}

/* Electrode Cable Animation */
.electrode-cable {
    fill: none;
    stroke: #64748b;
    stroke-width: 3;
    stroke-linecap: round;
    stroke-dasharray: 200;
    stroke-dashoffset: 200;
    transition: stroke-dashoffset 0.8s ease;
}

.placed-electrode.visible .electrode-cable {
    stroke-dashoffset: 0;
    animation: cablePulse 3s ease-in-out infinite;
}

@keyframes cablePulse {
    0%, 100% { stroke: #64748b; }
    50% { stroke: var(--accent); }
}

/* Electrode Placement Target Animation */
.electrode-target {
    fill: var(--accent-light);
    stroke: var(--accent);
    stroke-width: 2;
    stroke-dasharray: 4 4;
    animation: targetPulse 1s ease-in-out infinite;
}

@keyframes targetPulse {
    0%, 100% { transform: scale(1); opacity: 0.8; }
    50% { transform: scale(1.1); opacity: 1; }
}

/* Zone Drag Over State */
.prep-zone.drag-over {
    transform: scale(1.15);
    filter: drop-shadow(0 0 12px var(--accent));
}

/* Dragging Tool Cursor */
.tool-icon.dragging {
    opacity: 0.5;
    cursor: grabbing !important;
}

/* --- Calibration Step --- */
.calib-explanation {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
    margin-bottom: 24px;
}

.calib-info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 16px;
}

.calib-info-item {
    padding: 16px;
    background: var(--bg-primary);
    border: 1px solid var(--border-light);
    border-radius: var(--radius);
}

.calib-info-item i {
    color: var(--accent);
    margin-bottom: 8px;
    font-size: 1.1rem;
}

.calib-info-item strong {
    display: block;
    font-size: 0.9rem;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.calib-info-item p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* Calibration Workspace */
.calibration-workspace {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
}

.calib-machine {
    display: grid;
    grid-template-columns: 1fr 320px;
    gap: 24px;
}

.calib-display {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
}

.calib-display canvas {
    width: 100%;
    height: auto;
    background: #1e293b;
    border-radius: var(--radius-sm);
    margin-bottom: 16px;
}

.calib-readouts {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
}

.readout {
    text-align: center;
    padding: 12px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
}

.readout-label {
    display: block;
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-bottom: 4px;
}

.readout-value {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-primary);
    font-family: var(--font-mono);
}

/* Calibration Controls */
.calib-controls {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.control-group {
    padding: 14px;
    background: var(--bg-primary);
    border: 1px solid var(--border-light);
    border-radius: var(--radius);
}

.control-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.control-group input[type="range"] {
    width: 100%;
    height: 6px;
    background: var(--border);
    border-radius: 3px;
    appearance: none;
    margin-bottom: 6px;
}

.control-group input[type="range"]::-webkit-slider-thumb {
    appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--accent);
    cursor: pointer;
}

.control-group span {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--accent);
}

.control-hint {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 6px;
}

.control-group select {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--bg-card);
    color: var(--text-primary);
    font-size: 0.9rem;
}

.toggle-group {
    display: flex;
    gap: 8px;
}

.toggle-btn {
    flex: 1;
    padding: 10px;
    border: 1px solid var(--border);
    background: var(--bg-card);
    color: var(--text-secondary);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.85rem;
    font-weight: 500;
    transition: var(--transition);
}

.toggle-btn.active {
    background: var(--accent);
    border-color: var(--accent);
    color: white;
}

/* --- Recording Step --- */
.recording-workspace {
    display: grid;
    grid-template-columns: 1fr 320px;
    gap: 24px;
    align-items: start;
}

.recording-display {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
}

/* Recording Sidebar */
.recording-sidebar {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.condition-selector-panel {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 20px;
}

.condition-selector-panel > h4 {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.condition-selector-panel > h4 i {
    color: var(--accent);
}

.condition-cards-vertical {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.condition-cards-vertical .condition-card {
    padding: 12px 14px;
    text-align: left;
}

.condition-cards-vertical .condition-card-header {
    display: flex;
    align-items: center;
    gap: 10px;
}

.condition-cards-vertical .condition-card i {
    font-size: 1rem;
    margin-bottom: 0;
}

.condition-cards-vertical .condition-name {
    flex: 1;
    margin-bottom: 0;
}

/* Condition Info Panel */
.condition-info-panel {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 20px;
}

.condition-info-panel > h4 {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.condition-info-panel > h4 i {
    color: var(--accent);
}

.condition-info-panel > p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 12px;
}

.condition-info-panel .condition-characteristics {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.condition-info-panel .condition-characteristics ul {
    margin: 0;
    padding-left: 18px;
}

.condition-info-panel .condition-characteristics li {
    margin-bottom: 4px;
}

.display-header {
    margin-bottom: 20px;
}

.rec-indicator {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 12px;
    background: var(--danger-light);
    border: 1px solid var(--danger);
    border-radius: var(--radius-sm);
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--danger);
    margin-bottom: 16px;
}

.rec-dot {
    width: 8px;
    height: 8px;
    background: var(--danger);
    border-radius: 50%;
    animation: pulse-rec 1s infinite;
}

@keyframes pulse-rec {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.3; }
}

/* Condition Cards */
.condition-selector-visual {
    margin-bottom: 20px;
}

.condition-selector-visual > label {
    display: block;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 12px;
}

.condition-cards {
    display: flex;
    gap: 12px;
}

.condition-card {
    flex: 1;
    padding: 16px;
    background: var(--bg-primary);
    border: 2px solid var(--border);
    border-radius: var(--radius);
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
}

.condition-card:hover {
    border-color: var(--accent-border);
}

.condition-card.selected {
    border-color: var(--accent);
    background: var(--accent-light);
}

.condition-card i {
    font-size: 1.5rem;
    color: var(--text-muted);
    margin-bottom: 8px;
    display: block;
}

.condition-card.selected i {
    color: var(--accent);
}

.condition-name {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-primary);
    display: block;
    margin-bottom: 8px;
}

.condition-indicator {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    display: inline-block;
}

.condition-indicator.healthy { background: var(--success); }
.condition-indicator.tachycardia { background: var(--warning); }
.condition-indicator.bradycardia { background: var(--danger); }
.condition-indicator.irregular { background: #8b5cf6; }

/* Contraction Controls */
.contraction-controls {
    margin-top: 16px;
}

.contraction-controls > label {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 10px;
    display: block;
}

.contraction-btns {
    display: flex;
    gap: 8px;
}

.contract-btn {
    flex: 1;
    padding: 10px 12px;
    border: 1px solid var(--border);
    background: var(--bg-card);
    color: var(--text-secondary);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.85rem;
    transition: var(--transition);
}

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

.contract-btn.active {
    background: var(--accent);
    border-color: var(--accent);
    color: white;
}

/* Signal Display */
.signal-display {
    background: #1e293b;
    border-radius: var(--radius);
    padding: 16px;
    margin-bottom: 12px;
    position: relative;
    overflow: hidden;
}

.signal-display canvas {
    width: 100%;
    height: auto;
    display: block;
    min-height: 200px;
}

.signal-annotations {
    position: absolute;
    top: 20px;
    right: 20px;
    font-size: 0.75rem;
    color: rgba(255, 255, 255, 0.8);
    text-align: right;
    pointer-events: none;
    max-width: 200px;
}

.signal-scale-info {
    text-align: center;
    font-size: 0.75rem;
    color: var(--text-muted);
    padding: 8px 0;
    margin-bottom: 12px;
}

/* Signal Quality Indicator */
.signal-quality-indicator {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 12px;
    margin-bottom: 16px;
}

.quality-label {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.quality-label i {
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: var(--success-light);
    color: var(--success);
    font-size: 0.6rem;
    animation: pulse-indicator 2s ease-in-out infinite;
}

.quality-status {
    display: flex;
    align-items: center;
    gap: 12px;
}

.quality-value {
    font-weight: 600;
    font-size: 0.9rem;
    min-width: 60px;
}

.quality-value.good {
    color: var(--success);
}

.quality-value.warning {
    color: var(--warning);
}

.quality-value.poor {
    color: var(--danger);
}

.quality-bar {
    flex: 1;
    height: 6px;
    background: var(--border);
    border-radius: 3px;
    overflow: hidden;
}

.quality-fill {
    height: 100%;
    background: var(--success);
    transition: all 0.3s ease;
}

.quality-message {
    margin-top: 8px;
    font-size: 0.75rem;
    color: var(--text-muted);
}

@keyframes pulse-indicator {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.6; }
}

/* Signal Speed Control */
.signal-speed-control {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
    padding: 12px;
    background: var(--bg-primary);
    border-radius: var(--radius);
}

.signal-speed-control > label {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.speed-buttons {
    display: flex;
    gap: 6px;
}

.speed-btn {
    padding: 6px 12px;
    border: 1px solid var(--border);
    background: var(--bg-card);
    color: var(--text-secondary);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.8rem;
    transition: var(--transition);
}

.speed-btn.active {
    background: var(--accent);
    border-color: var(--accent);
    color: white;
}

.speed-hint {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-left: auto;
}

/* Real-time Metrics */
.rt-metrics {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
    margin-bottom: 20px;
}

.metric {
    text-align: center;
    padding: 12px;
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
}

.metric-label {
    display: block;
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-bottom: 4px;
}

.metric-value {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--accent);
    font-family: var(--font-mono);
}

/* Recording Controls */
.rec-controls {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px;
    background: var(--bg-primary);
    border-radius: var(--radius);
}

.btn-record {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 20px;
    background: var(--danger);
    border: none;
    border-radius: var(--radius);
    color: white;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

.btn-record:hover {
    background: #dc2626;
}

.btn-stop {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 20px;
    background: var(--text-secondary);
    border: none;
    border-radius: var(--radius);
    color: white;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
}

.btn-save {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 20px;
    background: var(--success);
    border: none;
    border-radius: var(--radius);
    color: white;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
}

.trials-saved {
    margin-left: auto;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

#trial-count {
    font-weight: 600;
    color: var(--accent);
}

/* Condition Info */
.condition-info {
    margin-top: 20px;
    padding: 16px;
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
}

.condition-info h4 {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.condition-info p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* Force Gauge Container */
.force-gauge-container {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 20px;
}

.force-gauge-container h4 {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.force-gauge-container h4 i {
    color: var(--accent);
}

.force-instruction {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 16px;
}

.force-gauge {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 16px;
}

.gauge-bg {
    flex: 1;
    height: 24px;
    background: var(--border);
    border-radius: 12px;
    overflow: hidden;
}

.gauge-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--success) 0%, var(--warning) 50%, var(--danger) 100%);
    border-radius: 12px;
    width: 0%;
    transition: width 0.2s ease;
}

.gauge-value {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    min-width: 50px;
}

#force-slider {
    width: 100%;
    margin-bottom: 20px;
}

/* --- Analysis Step --- */
.analysis-workspace {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
}

.analysis-tabs {
    display: flex;
    gap: 8px;
    margin-bottom: 20px;
    border-bottom: 1px solid var(--border);
    padding-bottom: 16px;
}

.analysis-tab {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 16px;
    border: 1px solid var(--border);
    background: var(--bg-primary);
    color: var(--text-secondary);
    border-radius: var(--radius);
    cursor: pointer;
    font-size: 0.85rem;
    transition: var(--transition);
}

.analysis-tab:hover {
    border-color: var(--accent-border);
}

.analysis-tab.active {
    background: var(--accent);
    border-color: var(--accent);
    color: white;
}

.analysis-tab i {
    font-size: 0.9rem;
}

.analysis-panels {
    margin-bottom: 20px;
}

.analysis-panel {
    display: none;
}

.analysis-panel.active {
    display: block;
}

.analysis-panel canvas {
    width: 100%;
    height: auto;
    background: #1e293b;
    border-radius: var(--radius);
    margin-bottom: 16px;
}

.analysis-controls-row {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 12px;
    background: var(--bg-primary);
    border-radius: var(--radius);
    margin-bottom: 16px;
}

.analysis-controls-row label {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.analysis-controls-row select,
.analysis-controls-row input[type="range"] {
    padding: 8px 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--bg-card);
    color: var(--text-primary);
    font-size: 0.85rem;
}

.analysis-stats {
    padding: 16px;
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* Comparison Grid */
.comparison-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}

.comparison-cell {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
}

.comparison-cell h4 {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 12px;
}

.condition-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

.condition-dot.healthy { background: var(--success); }
.condition-dot.tachycardia { background: var(--warning); }
.condition-dot.bradycardia { background: var(--danger); }
.condition-dot.irregular { background: #8b5cf6; }

.comparison-cell canvas {
    width: 100%;
    height: auto;
    background: #1e293b;
    border-radius: var(--radius-sm);
    margin-bottom: 12px;
}

.comp-stats {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

/* Analysis Summary */
.analysis-summary {
    margin-top: 24px;
}

.summary-card {
    text-align: center;
    padding: 32px;
    background: var(--success-light);
    border: 1px solid #a7f3d0;
    border-radius: var(--radius-lg);
}

.summary-card i {
    font-size: 2.5rem;
    color: var(--success);
    margin-bottom: 16px;
}

.summary-card h4 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
}

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

/* --- Download Section --- */
.download-section {
    display: flex;
    gap: 16px;
    justify-content: center;
    margin: 24px 0;
    flex-wrap: wrap;
}

.btn-download,
.btn-download-data {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 14px 28px;
    border: none;
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

.btn-download {
    background: linear-gradient(135deg, #10b981, #059669);
    color: white;
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.3);
}

.btn-download:hover {
    background: linear-gradient(135deg, #059669, #047857);
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(16, 185, 129, 0.4);
}

.btn-download-data {
    background: linear-gradient(135deg, #3b82f6, #2563eb);
    color: white;
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

.btn-download-data:hover {
    background: linear-gradient(135deg, #2563eb, #1d4ed8);
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(59, 130, 246, 0.4);
}

.btn-download i,
.btn-download-data i {
    font-size: 1.1rem;
}

/* --- Modal --- */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 20px;
}

.modal {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    max-width: 600px;
    width: 100%;
    max-height: 80vh;
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow-lg);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 24px;
    border-bottom: 1px solid var(--border);
}

.modal-header h3 {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.modal-header h3 i {
    color: var(--accent);
}

.modal-close {
    width: 32px;
    height: 32px;
    border: none;
    background: var(--bg-primary);
    border-radius: 50%;
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.modal-close:hover {
    background: var(--border);
    color: var(--text-primary);
}

.modal-body {
    padding: 24px;
    overflow-y: auto;
}

.glossary-search {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    margin-bottom: 20px;
}

.glossary-search i {
    color: var(--text-muted);
}

.glossary-search input {
    flex: 1;
    border: none;
    background: transparent;
    color: var(--text-primary);
    font-size: 0.9rem;
    outline: none;
}

.glossary-search input::placeholder {
    color: var(--text-muted);
}

.glossary-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

/* --- Responsive --- */
@media (max-width: 1200px) {
    .equipment-lab {
        grid-template-columns: 1fr;
    }
    
    .calib-machine {
        grid-template-columns: 1fr;
    }
    
    .recording-workspace {
        grid-template-columns: 1fr;
    }
    
    .science-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 992px) {
    #sidebar-nav {
        width: 72px;
    }
    
    .sidebar-header h2,
    .sidebar-header p,
    .lab-title,
    .step-content,
    .btn-glossary span {
        display: none;
    }
    
    .logo-image {
        max-height: 40px;
    }
    
    .nav-step {
        justify-content: center;
        padding: 12px;
    }
    
    #main-content {
        margin-left: 72px;
    }

    .lab-reset-btn {
        top: 12px;
        right: 12px;
    }
    
    .body-muscle-container {
        grid-template-columns: 1fr;
    }
    
    .comparison-grid {
        grid-template-columns: 1fr;
    }
    
    .info-grid {
        grid-template-columns: 1fr;
    }
    
    .calib-info-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    #sidebar-nav {
        position: fixed;
        bottom: 0;
        left: 0;
        right: 0;
        top: auto;
        width: 100%;
        height: auto;
        max-height: 80px;
        flex-direction: row;
        justify-content: space-around;
        padding: 8px 4px;
        z-index: 1000;
        border-top: 1px solid var(--border);
        border-right: none;
        overflow-x: auto;
    }
    
    .sidebar-header,
    .sidebar-footer,
    .step-content,
    .step-num {
        display: none;
    }
    
    .nav-steps {
        display: flex;
        flex-direction: row;
        width: 100%;
        justify-content: space-around;
        gap: 4px;
    }
    
    .nav-step {
        flex-direction: column;
        padding: 8px 12px;
        gap: 4px;
        min-width: auto;
        flex: 1;
        align-items: center;
        justify-content: center;
    }
    
    .nav-step .step-indicator {
        width: 28px;
        height: 28px;
        font-size: 0.75rem;
    }
    
    .nav-step .step-indicator i {
        font-size: 0.7rem;
    }

    .lab-reset-btn {
        top: 10px;
        right: 10px;
        padding: 8px 12px;
        font-size: 0.8rem;
        z-index: 1400;
    }
    
    .nav-step .step-content {
        display: none;
    }
    
    #main-content {
        margin-left: 0;
        margin-bottom: 80px;
        padding: 16px;
    }
    
    .lab-step {
        padding: 16px;
    }
    
    .section-header h2 {
        font-size: 1.25rem;
    }
    
    /* Canvas and SVG responsiveness */
    canvas {
        max-width: 100%;
        height: auto !important;
    }
    
    .body-svg,
    .arm-svg {
        width: 100%;
        max-width: 280px;
        height: auto;
        margin: 0 auto;
        display: block;
    }
    
    .body-diagram {
        display: flex;
        justify-content: center;
        padding: 16px;
    }
    
    .body-muscle-container {
        grid-template-columns: 1fr;
        gap: 16px;
    }
    
    .muscle-info-card {
        order: -1;
    }
    
    /* Equipment grid */
    .equipment-bench {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
    }
    
    .equipment-item {
        padding: 16px;
    }
    
    .equip-visual {
        font-size: 1.5rem;
        height: 60px;
    }
    
    .equip-label {
        font-size: 0.75rem;
    }
    
    /* Prep workspace */
    .arm-container {
        padding: 12px;
    }
    
    .arm-svg {
        max-width: 100%;
        width: 100%;
    }
    
    /* Horizontal progress bar responsive */
    .prep-progress-bar {
        flex-wrap: wrap;
        padding: 12px;
        gap: 8px;
    }
    
    .prep-step-indicator .step-circle {
        width: 36px;
        height: 36px;
    }
    
    .prep-step-indicator .step-circle i {
        font-size: 0.8rem;
    }
    
    .prep-step-indicator .step-name {
        font-size: 0.7rem;
    }
    
    .step-connector {
        width: 30px;
        margin: 0 4px;
        margin-bottom: 20px;
    }
    
    /* Floating impedance responsive */
    .floating-impedance {
        position: relative;
        top: auto;
        right: auto;
        margin-bottom: 16px;
        transform: none;
        opacity: 1;
        pointer-events: auto;
    }
    
    .floating-impedance.visible {
        transform: none;
    }
    
    .impedance-ring {
        width: 56px;
        height: 56px;
    }
    
    /* Prep main area responsive */
    .prep-main-area {
        grid-template-columns: 1fr;
        gap: 16px;
    }
    
    /* Collapsible steps responsive */
    .collapsible-step .step-header {
        padding: 10px 12px;
    }
    
    .step-header-left .tool-icon {
        width: 36px;
        height: 36px;
    }
    
    .step-title strong {
        font-size: 0.85rem;
    }
    
    .step-subtitle {
        font-size: 0.7rem;
    }
    
    .step-body {
        padding: 12px;
    }
    
    .electrode-tray .electrode-pick {
        width: 24px;
        height: 24px;
        font-size: 0.6rem;
    }
    
    .tool-steps {
        gap: 12px;
    }
    
    .tool-step {
        flex-direction: column;
        text-align: center;
        padding: 12px;
    }
    
    .tool-icon {
        margin: 0 auto;
    }
    
    /* Calibration */
    .calib-readouts {
        grid-template-columns: repeat(2, 1fr);
        gap: 8px;
    }
    
    .readout {
        padding: 8px;
    }
    
    .readout-label {
        font-size: 0.65rem;
    }
    
    .readout-value {
        font-size: 0.8rem;
    }
    
    .control-group {
        padding: 12px;
    }
    
    /* Recording */
    .recording-workspace {
        grid-template-columns: 1fr;
        gap: 16px;
    }
    
    .recording-sidebar {
        display: grid;
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
    }
    
    .condition-selector-panel {
        grid-column: span 2;
    }
    
    .condition-cards-vertical {
        display: flex;
        flex-direction: row;
        flex-wrap: wrap;
    }
    
    .condition-cards-vertical .condition-card {
        flex: 1 1 calc(50% - 4px);
        min-width: 140px;
    }
    
    .condition-info-panel {
        grid-column: span 1;
    }
    
    .force-gauge-container {
        grid-column: span 1;
    }
    
    .contraction-btns {
        flex-wrap: wrap;
    }
    
    .contract-btn {
        flex: 1 1 calc(50% - 4px);
        min-width: 80px;
    }
    
    .rt-metrics {
        grid-template-columns: repeat(2, 1fr);
        gap: 8px;
    }
    
    .metric {
        padding: 8px;
    }
    
    .rec-controls {
        flex-wrap: wrap;
        gap: 8px;
    }
    
    .btn-record,
    .btn-stop,
    .btn-save {
        flex: 1;
        min-width: 100px;
        padding: 10px 14px;
        font-size: 0.8rem;
    }
    
    /* Analysis */
    .analysis-tabs {
        flex-wrap: wrap;
        gap: 6px;
    }
    
    .analysis-tab {
        flex: 1 1 calc(50% - 3px);
        min-width: 120px;
        padding: 8px 12px;
        font-size: 0.75rem;
        justify-content: center;
    }
    
    .comparison-grid {
        grid-template-columns: 1fr;
    }
    
    /* Info cards */
    .info-grid {
        grid-template-columns: 1fr;
    }
    
    .info-card {
        padding: 16px;
    }
    
    /* Welcome section */
    .welcome-card {
        padding: 24px 16px;
    }
    
    .welcome-card h1 {
        font-size: 1.5rem;
    }
    
    .welcome-card p {
        font-size: 0.9rem;
    }
    
    /* Science section */
    .science-section-card {
        padding: 16px;
    }
    
    .science-grid {
        grid-template-columns: 1fr;
    }
    
    /* ECG Complex canvas */
    .ecg-preview-visualization {
        padding: 16px;
    }
    
    .ecg-preview-visualization canvas {
        height: 150px !important;
    }
    
    /* Signal display */
    .signal-display {
        padding: 12px;
    }
    
    .signal-display canvas {
        height: auto;
        min-height: 180px;
    }
    
    /* Force gauge */
    .force-gauge-container {
        padding: 16px;
    }
    
    /* Modal */
    .modal {
        max-width: calc(100% - 32px);
        margin: 16px;
    }
    
    .modal-header,
    .modal-body {
        padding: 16px;
    }
}

@media (max-width: 480px) {
    #main-content {
        padding: 12px;
    }
    
    .section-header h2 {
        font-size: 1.1rem;
    }
    
    .section-header p {
        font-size: 0.8rem;
    }
    
    .equipment-bench {
        grid-template-columns: repeat(2, 1fr);
        gap: 8px;
    }
    
    .equipment-item {
        padding: 12px;
    }
    
    .equip-visual {
        font-size: 1.25rem;
        height: 50px;
    }
    
    .equip-label {
        font-size: 0.7rem;
    }
    
    .btn-primary,
    .btn-record,
    .btn-stop,
    .btn-save {
        padding: 10px 16px;
        font-size: 0.8rem;
    }
    
    .condition-card {
        flex: 1 1 100%;
    }
    
    .contract-btn {
        flex: 1 1 calc(50% - 4px);
        font-size: 0.75rem;
        padding: 8px;
    }
    
    .analysis-tab {
        flex: 1 1 100%;
    }
    
    .nav-step {
        padding: 6px 8px;
    }
    
    .nav-step .step-indicator {
        width: 24px;
        height: 24px;
        font-size: 0.65rem;
    }
    
    .nav-step .step-indicator i {
        font-size: 0.6rem;
    }
    
    .calib-readouts {
        grid-template-columns: 1fr 1fr;
    }
    
    .rt-metrics {
        grid-template-columns: 1fr 1fr;
    }
    
    .welcome-card h1 {
        font-size: 1.25rem;
    }
    
    .info-card-header h3 {
        font-size: 0.9rem;
    }
    
    .prep-instruction-banner {
        flex-direction: column;
        text-align: center;
    }
}