:root {
    --bg-main: #f9fafb;
    --bg-sidebar: #ffffff;
    --bg-card: #ffffff;
    --border-main: #e5e7eb;
    --border-light: #f3f4f6;
    
    --text-primary: #111827;
    --text-secondary: #4b5563;
    --text-muted: #9ca3af;
    
    --accent-blue: #2563eb;
    --accent-slate: #0f172a;
    
    --risk-safe: #059669;
    --risk-warn: #d97706;
    --risk-danger: #dc2626;
    
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
}

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

body {
    font-family: 'Inter', -apple-system, sans-serif;
    background-color: var(--bg-main);
    color: var(--text-primary);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

.app-layout {
    display: flex;
    min-height: 100vh;
}

/* Sidebar */
.sidebar {
    width: 256px;
    background-color: var(--bg-sidebar);
    border-right: 1px solid var(--border-main);
    display: flex;
    flex-direction: column;
    position: sticky;
    top: 0;
    height: 100vh;
}

.brand {
    padding: 32px 24px;
    border-bottom: 1px solid var(--border-main);
}

.brand-title {
    font-size: 1.125rem;
    font-weight: 700;
    letter-spacing: -0.025em;
    color: var(--text-primary);
}

.brand-subtitle {
    font-size: 0.65rem;
    font-weight: 600;
    letter-spacing: 0.1em;
    color: var(--text-muted);
    margin-top: 4px;
}

.nav-group {
    padding: 24px 0;
    flex: 1;
}

.nav-header {
    padding: 0 24px;
    font-size: 0.65rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: 12px;
}

.nav-links {
    display: flex;
    flex-direction: column;
}

.nav-item {
    padding: 10px 24px;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    text-decoration: none;
    border-left: 2px solid transparent;
    transition: all 0.15s ease;
}

.nav-item:hover {
    color: var(--text-primary);
    background-color: var(--bg-main);
}

.nav-item.active {
    color: var(--accent-blue);
    background-color: #eff6ff;
    border-left-color: var(--accent-blue);
    font-weight: 600;
}

.sidebar-meta {
    padding: 24px;
    border-top: 1px solid var(--border-main);
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.meta-block {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.meta-label {
    font-size: 0.65rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    color: var(--text-muted);
}

.meta-value {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-primary);
}

/* Main Content */
.main-content {
    flex: 1;
    padding: 48px;
    overflow-y: auto;
}

.view-section {
    display: none;
    animation: fadeIn 0.3s ease;
}

.view-section.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(4px); }
    to { opacity: 1; transform: translateY(0); }
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 40px;
}

.header-titles h1 {
    font-size: 1.875rem;
    font-weight: 700;
    letter-spacing: -0.025em;
    color: var(--text-primary);
    margin-bottom: 8px;
}

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

.system-status {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 12px;
    background-color: #ecfdf5;
    color: var(--risk-safe);
    border-radius: 9999px;
    font-size: 0.7rem;
    font-weight: 600;
    letter-spacing: 0.05em;
}

.status-indicator {
    width: 6px;
    height: 6px;
    background-color: var(--risk-safe);
    border-radius: 50%;
}

/* KPI Grid */
.kpi-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 24px;
    margin-bottom: 40px;
}

.kpi-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-main);
    border-radius: 8px;
    padding: 24px;
    box-shadow: var(--shadow-sm);
}

.kpi-label {
    font-size: 0.7rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: 12px;
}

.kpi-value {
    font-size: 2rem;
    font-weight: 600;
    letter-spacing: -0.025em;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.kpi-value.highlight {
    color: var(--accent-blue);
}

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

.status-safe { color: var(--risk-safe); }
.status-warn { color: var(--risk-warn); }
.status-danger { color: var(--risk-danger); }

/* Chart Container */
.chart-container {
    background-color: var(--bg-card);
    border: 1px solid var(--border-main);
    border-radius: 8px;
    padding: 32px;
    box-shadow: var(--shadow-sm);
}

.chart-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
}

.chart-title {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
}

.chart-filters {
    display: flex;
    gap: 8px;
}

.filter-btn {
    background: transparent;
    border: 1px solid var(--border-main);
    padding: 6px 14px;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-secondary);
    border-radius: 6px;
    cursor: pointer;
    font-family: inherit;
}

.filter-btn:hover {
    border-color: var(--text-muted);
    color: var(--text-primary);
}

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

.chart-canvas-wrapper {
    height: 400px;
    width: 100%;
}

/* Architecture & Metrics */
.grid-2col {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 32px;
}

.info-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-main);
    border-radius: 8px;
    padding: 32px;
    box-shadow: var(--shadow-sm);
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
    letter-spacing: -0.025em;
    margin-bottom: 12px;
}

.card-text {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-bottom: 32px;
}

.steps-list {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.step-item {
    display: flex;
    gap: 16px;
}

.step-number {
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--accent-blue);
    padding-top: 4px;
}

.step-title {
    font-weight: 600;
    font-size: 0.95rem;
    margin-bottom: 4px;
}

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

.feature-block {
    margin-bottom: 24px;
    padding-bottom: 24px;
    border-bottom: 1px solid var(--border-light);
}

.feature-block:last-child {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.feature-title {
    font-weight: 600;
    font-size: 0.95rem;
    margin-bottom: 8px;
}

.feature-desc {
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.mt-24 {
    margin-top: 32px;
}

.benchmark-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin-top: 24px;
}

.stat-item {
    padding: 24px;
    background-color: var(--bg-main);
    border-radius: 6px;
    border: 1px solid var(--border-light);
}

.stat-label {
    font-size: 0.7rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: 16px;
}

.stat-comparison {
    display: flex;
    align-items: baseline;
    gap: 12px;
    margin-bottom: 12px;
}

.stat-old {
    font-size: 1rem;
    color: var(--text-muted);
    text-decoration: line-through;
}

.stat-new {
    font-size: 1.75rem;
    font-weight: 600;
    color: var(--accent-slate);
    letter-spacing: -0.025em;
}

.stat-note {
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--risk-safe);
}

/* Explorer View */
.grid-explorer {
    display: grid;
    grid-template-columns: 320px 1fr;
    gap: 32px;
}

.simulator-panel {
    margin-top: 24px;
}

.slider-header {
    display: flex;
    justify-content: space-between;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.slider-value {
    color: var(--accent-blue);
}

input[type="range"] {
    width: 100%;
    margin-bottom: 32px;
    accent-color: var(--accent-slate);
}

.sim-metrics {
    display: flex;
    flex-direction: column;
    gap: 16px;
    padding: 20px;
    background-color: var(--bg-main);
    border-radius: 6px;
    border: 1px solid var(--border-light);
    margin-bottom: 16px;
}

.sim-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.875rem;
}

.sim-label {
    color: var(--text-secondary);
}

.sim-val {
    font-weight: 600;
}

.sim-val.highlight {
    font-size: 1.1rem;
    color: var(--accent-blue);
}

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

.table-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
}

.data-table-card {
    display: flex;
    flex-direction: column;
    height: 700px;
}

.table-container {
    flex: 1;
    overflow-y: auto;
    border: 1px solid var(--border-light);
    border-radius: 6px;
}

table {
    width: 100%;
    border-collapse: collapse;
}

th {
    position: sticky;
    top: 0;
    background-color: var(--bg-main);
    padding: 12px 16px;
    text-align: left;
    font-size: 0.7rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    border-bottom: 1px solid var(--border-main);
}

td {
    padding: 12px 16px;
    font-size: 0.875rem;
    color: var(--text-primary);
    border-bottom: 1px solid var(--border-light);
}

.num-col {
    text-align: right;
}

td.num-col {
    font-variant-numeric: tabular-nums;
}

tr:last-child td {
    border-bottom: none;
}

tr:hover td {
    background-color: #f8fafc;
}