:root {
    --bpc-primary: #DC2626;
    --bpc-primary-strong: #B91C1C;
    --bpc-secondary: #155E75;
    --bpc-secondary-strong: #0F3E4F;
    --bpc-text: #0F172A;
    --bpc-text-muted: #64748B;
    --bpc-surface: #F8FAFC;
    --bpc-water: #F0F9FF;
    --bpc-border-soft: #E2E8F0;
    --bpc-link: #155E75;
    --bpc-accent: var(--bpc-primary);
    --bpc-gradient: linear-gradient(135deg, #DC2626, #B91C1C);
    --maxw: 900px;
    --radius: 16px;
    --shadow: 0 8px 25px rgba(0, 0, 0, .08);
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 48px;
}

* {
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    color: var(--bpc-text);
    background: var(--bpc-surface);
    margin: 0;
    padding: 0;
    line-height: 1.6;
}

.container {
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 0 var(--spacing-md) var(--spacing-lg);
}

.header {
    text-align: center;
    padding: var(--spacing-lg) 0;
    background: #141414;
    box-shadow: 0 8px 30px rgba(0,0,0,0.4);
    margin-bottom: var(--spacing-md);
}

.header h1 {
    color: var(--bpc-primary);
    font-size: 32px;
    margin: 0 0 var(--spacing-xs) 0;
    font-weight: 800;
}

.header p {
    color: var(--bpc-text-muted);
    font-size: 14px;
    margin: 0;
}

/* Tabs Navigation */
.tabs-nav {
    display: flex;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-md);
    background: #141414;
    padding: var(--spacing-sm);
    border-radius: var(--radius);
    box-shadow: 0 8px 30px rgba(0,0,0,0.4);
}

.tab-btn {
    flex: 1;
    padding: var(--spacing-sm);
    border: 2px solid transparent;
    background: transparent;
    color: var(--bpc-text-muted);
    border-radius: 8px;
    font-weight: 600;
    font-size: 14px;
    cursor: pointer;
    transition: all 0.3s;
    text-align: center;
}

.tab-btn:hover {
    background: var(--bpc-surface);
}

.tab-btn.active {
    background: var(--bpc-gradient);
    color: white;
    box-shadow: 0 4px 12px rgba(220, 38, 38, 0.3);
}

.tab-content {
    display: none;
}

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

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

/* Sport Selector */
.sport-selector {
    display: flex;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-md);
    background: #141414;
    padding: var(--spacing-sm);
    border-radius: var(--radius);
    box-shadow: 0 8px 30px rgba(0,0,0,0.4);
}

.sport-btn {
    flex: 1;
    padding: var(--spacing-sm);
    border: 2px solid transparent;
    background: transparent;
    color: var(--bpc-text-muted);
    border-radius: 8px;
    font-weight: 600;
    font-size: 14px;
    cursor: pointer;
    transition: all 0.3s;
    text-align: center;
}

.sport-btn:hover {
    background: var(--bpc-surface);
}

.sport-btn.active {
    background: var(--bpc-gradient);
    color: white;
    box-shadow: 0 4px 12px rgba(220, 38, 38, 0.3);
}

/* Sport Selector Compact (for Compare tab) */
.sport-selector-compact {
    display: flex;
    gap: 4px;
    margin-bottom: 12px;
    justify-content: center;
}

.sport-btn-compact {
    padding: 6px 12px;
    border: 2px solid var(--bpc-border-soft);
    background: #141414;
    color: var(--bpc-text);
    border-radius: 6px;
    font-size: 18px;
    cursor: pointer;
    transition: all 0.2s;
    opacity: 0.5;
}

.sport-btn-compact:hover {
    opacity: 0.8;
    border-color: var(--bpc-primary);
}

.sport-btn-compact.active {
    opacity: 1;
    border-color: var(--bpc-primary);
    background: var(--bpc-surface);
}

.card {
    background: #141414;
    border-radius: var(--radius);
    padding: var(--spacing-lg);
    box-shadow: 0 8px 30px rgba(0,0,0,0.4);
    margin-bottom: var(--spacing-md);
}

.tss-display {
    text-align: center;
    padding: var(--spacing-lg);
    background: var(--bpc-gradient);
    border-radius: var(--radius);
    color: white;
    margin-bottom: var(--spacing-lg);
}

.tss-display .label {
    font-size: 14px;
    opacity: 0.9;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.tss-display .value {
    font-size: 72px;
    font-weight: 800;
    line-height: 1;
    margin: var(--spacing-sm) 0;
}

.tss-display.blue {
    background: linear-gradient(135deg, #3B82F6, #2563EB);
}

.tss-display.rose {
    background: linear-gradient(135deg, #F43F5E, #E11D48);
}

.tss-display .zone {
    font-size: 16px;
    opacity: 0.95;
    font-weight: 600;
}

.slider-group {
    margin-bottom: var(--spacing-lg);
}

.slider-group label {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
    color: var(--bpc-text);
}

.slider-group .value-display {
    color: var(--bpc-primary);
    font-size: 18px;
}

input[type="range"] {
    width: 100%;
    height: 8px;
    border-radius: 4px;
    background: var(--bpc-border-soft);
    outline: none;
    -webkit-appearance: none;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--bpc-gradient);
    cursor: pointer;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

input[type="range"]::-moz-range-thumb {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--bpc-gradient);
    cursor: pointer;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
    border: none;
}

.helper-text {
    font-size: 12px;
    color: var(--bpc-text-muted);
    margin-top: var(--spacing-xs);
    font-style: italic;
}

.education-section {
    background: var(--bpc-water);
    padding: var(--spacing-md);
    border-radius: var(--radius);
    border: 1px solid rgba(255,255,255,0.08);
}

.education-section h3 {
    color: var(--bpc-secondary);
    font-size: 18px;
    margin: 0 0 var(--spacing-sm) 0;
    font-weight: 700;
}

.formula-box {
    background: #141414;
    padding: var(--spacing-md);
    border-radius: 8px;
    text-align: center;
    font-family: 'Courier New', monospace;
    font-size: 18px;
    font-weight: 600;
    color: var(--bpc-secondary);
    margin: var(--spacing-md) 0;
    border: 2px solid var(--bpc-border-soft);
}

.breakdown {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.breakdown-item {
    text-align: center;
    padding: var(--spacing-md);
    background: #141414;
    border-radius: 8px;
    border: 1px solid rgba(255,255,255,0.08);
}

.breakdown-item .label {
    font-size: 12px;
    color: var(--bpc-text-muted);
    margin-bottom: var(--spacing-xs);
}

.breakdown-item .value {
    font-size: 24px;
    font-weight: 700;
    color: var(--bpc-text);
}

.breakdown-item .impact {
    font-size: 10px;
    color: var(--bpc-text-muted);
    margin-top: var(--spacing-xs);
}

.presets {
    margin-top: var(--spacing-md);
}

.presets h4 {
    font-size: 14px;
    font-weight: 600;
    color: var(--bpc-text);
    margin: 0 0 var(--spacing-sm) 0;
}

.preset-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: var(--spacing-sm);
}

.preset-btn {
    padding: var(--spacing-sm);
    border: 2px solid var(--bpc-border-soft);
    border-radius: 8px;
    background: #141414;
    cursor: pointer;
    transition: all 0.2s;
    text-align: left;
}

.preset-btn:hover {
    border-color: var(--bpc-primary);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.preset-btn .name {
    font-size: 13px;
    font-weight: 600;
    color: var(--bpc-text);
    margin-bottom: 4px;
}

.preset-btn .details {
    font-size: 11px;
    color: var(--bpc-text-muted);
}

.info-box {
    background: #141414;
    padding: var(--spacing-md);
    border-radius: 8px;
    border-left: 4px solid var(--bpc-primary);
    margin: var(--spacing-md) 0;
}

.info-box p {
    margin: 0;
    font-size: 13px;
    line-height: 1.6;
    color: var(--bpc-text-muted);
}

.zone-guide {
    margin-top: var(--spacing-md);
}

.zone-item {
    display: flex;
    justify-content: space-between;
    padding: var(--spacing-xs) var(--spacing-sm);
    margin-bottom: 4px;
    background: #141414;
    border-radius: 6px;
    font-size: 12px;
}

.zone-item .zone-name {
    font-weight: 600;
    color: var(--bpc-text);
}

.zone-item .zone-if {
    color: var(--bpc-text-muted);
    font-family: 'Courier New', monospace;
}

/* Compare Page Styles */
.compare-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
}

.session-card {
    background: #141414;
    border-radius: var(--radius);
    padding: var(--spacing-md);
    box-shadow: 0 8px 30px rgba(0,0,0,0.4);
    border-top: 4px solid #3B82F6;
}

.session-card.rose {
    border-top-color: #F43F5E;
}

.comparison-result {
    padding: var(--spacing-md);
    border-radius: var(--radius);
    border-left: 4px solid var(--bpc-secondary);
    margin-bottom: var(--spacing-md);
}

.comparison-result.similar {
    background: #EEF2FF;
    border-color: #6366F1;
}

.comparison-result.different {
    background: var(--bpc-surface);
    border-color: var(--bpc-text-muted);
}

.alert-box {
    background: #FEF3C7;
    border: 1px solid #FCD34D;
    border-radius: 8px;
    padding: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.alert-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-sm);
}

.alert-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    background: #141414;
    padding: var(--spacing-xs);
    border-radius: 6px;
    font-size: 12px;
}

/* Simulation Page Styles */
.plan-selector {
    display: flex;
    gap: var(--spacing-xs);
    overflow-x: auto;
    padding-bottom: var(--spacing-xs);
    margin-bottom: var(--spacing-md);
}

.plan-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--bpc-border-soft);
    border-radius: 8px;
    background: #141414;
    cursor: pointer;
    font-size: 12px;
    font-weight: 600;
    white-space: nowrap;
    transition: all 0.2s;
}

.plan-btn.active {
    background: var(--bpc-secondary);
    color: white;
    border-color: var(--bpc-secondary);
}

.plan-btn:hover:not(.active) {
    border-color: var(--bpc-secondary);
}

.metrics-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
    margin: var(--spacing-md) 0;
}

.metric-card {
    background: #141414;
    border-radius: var(--radius);
    padding: var(--spacing-md);
    text-align: center;
    box-shadow: 0 8px 30px rgba(0,0,0,0.4);
}

.metric-card .label {
    font-size: 12px;
    color: var(--bpc-text-muted);
    text-transform: uppercase;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.metric-card .value {
    font-size: 32px;
    font-weight: 800;
    color: var(--bpc-text);
}

.metric-card.blue .value {
    color: #3B82F6;
}

.metric-card.rose .value {
    color: #F43F5E;
}

.metric-card.emerald .value {
    color: #10B981;
}

.metric-card.amber .value {
    color: #F59E0B;
}

.risk-alert {
    padding: var(--spacing-md);
    border-radius: var(--radius);
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: start;
    gap: var(--spacing-sm);
}

.risk-alert.high {
    background: #FEE2E2;
    border: 2px solid #EF4444;
    color: #991B1B;
}

.risk-alert.moderate {
    background: #FEF3C7;
    border: 2px solid #F59E0B;
    color: #92400E;
}

.risk-alert.safe {
    background: #D1FAE5;
    border: 2px solid #10B981;
    color: #065F46;
}

.chart-container {
    background: #141414;
    border-radius: var(--radius);
    padding: var(--spacing-md);
    box-shadow: 0 8px 30px rgba(0,0,0,0.4);
    margin: var(--spacing-md) 0;
}

@media (max-width: 768px) {
    .compare-grid,
    .breakdown,
    .alert-grid {
        grid-template-columns: 1fr;
    }

    .tss-display .value {
        font-size: 56px;
    }

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

    .tabs-nav {
        flex-direction: column;
    }

    .metrics-grid {
        grid-template-columns: 1fr;
    }
}