:root {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-card: rgba(30, 41, 59, 0.7);
    --border-color: #334155;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --accent: #6366f1;
    --accent-hover: #4f46e5;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --radius: 12px;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
}

body {
    background-color: var(--bg-primary);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
}

/* Layout */
.sidebar {
    width: 260px;
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    padding: 1.5rem 1rem;
    position: fixed;
    height: 100vh;
    overflow-y: auto;
}

.sidebar .brand {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-main);
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 1.5rem;
}

.brand-icon {
    width: 32px;
    height: 32px;
    background: var(--accent);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
}

.nav-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    color: var(--text-muted);
    text-decoration: none;
    border-radius: 8px;
    font-weight: 500;
    transition: all 0.2s ease;
}

.nav-link:hover, .nav-link.active {
    background: var(--accent);
    color: #fff;
}

.main-content {
    margin-left: 260px;
    flex: 1;
    padding: 2rem;
    max-width: 1400px;
}

/* Header */
.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.page-title {
    font-size: 1.75rem;
    font-weight: 700;
}

/* Grid & Cards */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.stat-label {
    color: var(--text-muted);
    font-size: 0.875rem;
    font-weight: 500;
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
}

.card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1.5rem;
    margin-bottom: 2rem;
}

.card-title {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* Tables */
.table-responsive {
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
    text-align: left;
}

th, td {
    padding: 0.875rem 1rem;
    border-bottom: 1px solid var(--border-color);
}

th {
    color: var(--text-muted);
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

tr:hover td {
    background: rgba(255, 255, 255, 0.02);
}

/* Badges */
.badge {
    display: inline-block;
    padding: 0.25rem 0.6rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
}

.badge-success { background: rgba(16, 185, 129, 0.15); color: var(--success); }
.badge-warning { background: rgba(245, 158, 11, 0.15); color: var(--warning); }
.badge-danger { background: rgba(239, 68, 68, 0.15); color: var(--danger); }
.badge-info { background: rgba(99, 102, 241, 0.15); color: var(--accent); }

/* Buttons */
.btn {
    padding: 0.6rem 1.2rem;
    border-radius: 8px;
    font-weight: 600;
    border: none;
    cursor: pointer;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    transition: background 0.2s ease;
}

.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-hover); }
.btn-danger { background: var(--danger); color: #fff; }
.btn-sm { padding: 0.35rem 0.75rem; font-size: 0.8rem; }

/* Forms & Modals */
.form-group {
    margin-bottom: 1.25rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

label {
    font-size: 0.875rem;
    color: var(--text-muted);
    font-weight: 500;
}

input, select, textarea {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    color: var(--text-main);
    padding: 0.65rem 0.85rem;
    border-radius: 8px;
    outline: none;
    font-size: 0.95rem;
}

input:focus, select:focus, textarea:focus {
    border-color: var(--accent);
}

.modal {
    position: fixed;
    top: 0; left: 0; width: 100vw; height: 100vh;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s ease;
}

.modal.active {
    opacity: 1;
    pointer-events: auto;
}

.modal-content {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 2rem;
    width: 100%;
    max-width: 500px;
}