:root {
    /* Color Palette - Clean Enterprise Light Theme */
    --bg-base: #f8fafc;
    --bg-surface: #ffffff;
    --bg-surface-hover: #f1f5f9;
    --bg-elevated: #ffffff;
    
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #64748b;
    
    --border-color: #e2e8f0;
    --border-hover: #cbd5e1;
    
    --accent-primary: #2563eb;
    --accent-glow: #eff6ff;
    
    /* Typography */
    --font-sans: 'Pretendard', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    
    /* Layout & Geometry */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-full: 9999px;
    
    --shadow-subtle: 0 1px 3px 0 rgba(0, 0, 0, 0.05), 0 1px 2px -1px rgba(0, 0, 0, 0.05);
    --shadow-card: 0 4px 6px -1px rgba(0, 0, 0, 0.03), 0 2px 4px -2px rgba(0, 0, 0, 0.03);
}

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

body {
    font-family: var(--font-sans);
    background-color: var(--bg-base);
    color: var(--text-primary);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Utilities */
.text-right { text-align: right; }
.text-muted { color: var(--text-muted); }
.text-primary { color: var(--text-primary); }
.font-medium { font-weight: 500; }
.p-0 { padding: 0 !important; }

/* Layout Structure */
.app-layout {
    display: flex;
    min-height: 100vh;
}

.sidebar {
    width: 240px;
    background-color: var(--bg-surface);
    border-right: 1px solid var(--border-color);
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
}

.brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 2.5rem;
}


.brand-text {
    font-weight: 700;
    font-size: 1.125rem;
    letter-spacing: -0.01em;
}

.nav-menu {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.6rem 1rem;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: var(--radius-md);
    font-weight: 500;
    font-size: 0.95rem;
    transition: all 0.15s ease;
}

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

.nav-item.active {
    background-color: var(--accent-glow);
    color: var(--accent-primary);
}

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow-x: hidden;
}

.topbar {
    height: 64px;
    padding: 0 2rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    background-color: var(--bg-surface);
}

.page-title {
    display: flex;
    align-items: center;
}

.page-title h1 {
    font-size: 1.125rem;
    font-weight: 600;
    letter-spacing: -0.01em;
}

.user-avatar {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-full);
    background-color: #e2e8f0;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.8rem;
    border: 1px solid var(--border-color);
}

.content-wrapper {
    padding: 2rem;
    max-width: 1400px;
    width: 100%;
    margin: 0 auto;
}

/* Alert */
.alert {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.25rem;
    border-radius: var(--radius-md);
    margin-bottom: 2rem;
    background-color: #fee2e2;
    border: 1px solid #fecaca;
    color: #991b1b;
}

.alert-icon {
    font-weight: bold;
    width: 24px;
    height: 24px;
    background-color: #ef4444;
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Metrics Grid */
.metrics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.metric-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-subtle);
}

.metric-header {
    margin-bottom: 0.75rem;
}

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

.metric-value {
    font-size: 1.75rem;
    font-weight: 600;
    letter-spacing: -0.02em;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    line-height: 1.2;
}

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

.metric-card.highlight {
    background-color: #f8fafc;
    border: 1px solid #cbd5e1;
}

/* Bento Grid */
.bento-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
}

@media (max-width: 1100px) {
    .bento-grid {
        grid-template-columns: 1fr;
    }
    .col-span-2 {
        grid-column: span 1 / span 1 !important;
    }
}

.col-span-2 {
    grid-column: span 2 / span 2;
}

.bento-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-card);
    display: flex;
    flex-direction: column;
}

.card-header {
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.card-header h2 {
    font-size: 1rem;
    font-weight: 600;
}

.card-body {
    padding: 1.5rem;
    flex: 1;
}

/* Refined Table */
.refined-table {
    width: 100%;
    border-collapse: collapse;
}

.refined-table th {
    padding: 1rem 1.5rem;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-color);
    text-align: left;
    background-color: #f8fafc;
}

.refined-table td {
    padding: 1rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
    font-size: 0.95rem;
}

.refined-table tbody tr:last-child td {
    border-bottom: none;
}

.user-identity {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.avatar-sm {
    width: 28px;
    height: 28px;
    border-radius: var(--radius-full);
    background-color: #f1f5f9;
    color: #475569;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.8rem;
    border: 1px solid #e2e8f0;
}

.user-name {
    font-weight: 500;
}

.badge {
    font-size: 0.85rem;
    padding: 0.2rem 0.5rem;
    background-color: #f1f5f9;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
}

/* Timeline / Stream */
.timeline {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.timeline-event {
    display: flex;
    gap: 1rem;
    position: relative;
}

.timeline-content {
    flex: 1;
}

.timeline-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.25rem;
}

.timeline-user {
    font-size: 0.9rem;
    font-weight: 500;
}

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

.timeline-metrics {
    display: flex;
    gap: 0.5rem;
    margin-top: 0.25rem;
}

.metric-pill {
    padding: 0.15rem 0.5rem;
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    background-color: #f1f5f9;
    color: var(--text-secondary);
}

.timeline-model {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-bottom: 0.25rem;
}

/* Empty States */
.empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 3rem 1rem;
    color: var(--text-muted);
    text-align: center;
}

.empty-state.small {
    padding: 1rem;
    font-size: 0.9rem;
}

/* Filter Select */
.filter-select {
    padding: 0.4rem 2rem 0.4rem 0.8rem;
    font-size: 0.9rem;
    color: var(--text-primary);
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    outline: none;
    appearance: none;
    cursor: pointer;
    background-image: url("data:image/svg+xml;charset=US-ASCII,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%22292.4%22%20height%3D%22292.4%22%3E%3Cpath%20fill%3D%22%23475569%22%20d%3D%22M287%2069.4a17.6%2017.6%200%200%200-13-5.4H18.4c-5%200-9.3%201.8-12.9%205.4A17.6%2017.6%200%200%200%200%2082.2c0%205%201.8%209.3%205.4%2012.9l128%20127.9c3.6%203.6%207.8%205.4%2012.8%205.4s9.2-1.8%2012.8-5.4L287%2095c3.5-3.5%205.4-7.8%205.4-12.8%200-5-1.9-9.2-5.5-12.8z%22%2F%3E%3C%2Fsvg%3E");
    background-repeat: no-repeat;
    background-position: right 0.7rem top 50%;
    background-size: 0.65rem auto;
    transition: border-color 0.15s ease;
}

.filter-select:hover {
    border-color: var(--border-hover);
}

.filter-select:focus {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 2px var(--accent-glow);
}