:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --danger: #dc2626;
    --success: #16a34a;
    --warning: #d97706;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-500: #6b7280;
    --gray-700: #374151;
    --gray-900: #111827;
    --radius: 8px;
    --shadow: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-lg: 0 4px 12px rgba(0,0,0,0.1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--gray-50);
    color: var(--gray-900);
    line-height: 1.6;
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

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

.sidebar {
    width: 260px;
    background: var(--gray-900);
    color: #fff;
    padding: 1.5rem 0;
    flex-shrink: 0;
}

.sidebar-brand {
    padding: 0 1.5rem 1.5rem;
    font-size: 1.2rem;
    font-weight: 700;
    border-bottom: 1px solid var(--gray-700);
    margin-bottom: 1rem;
}

.sidebar-nav a {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.6rem 1.5rem;
    color: var(--gray-300);
    transition: background 0.15s, color 0.15s;
}

.sidebar-nav a:hover,
.sidebar-nav a.active {
    background: var(--primary);
    color: #fff;
    text-decoration: none;
}

.sidebar-section {
    padding: 0.75rem 1.5rem 0.3rem;
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--gray-500);
}

.sidebar-user {
    padding: 1rem 1.5rem;
    border-top: 1px solid var(--gray-700);
    margin-top: auto;
    font-size: 0.875rem;
    color: var(--gray-300);
}

.main {
    flex: 1;
    padding: 2rem;
    max-width: 1200px;
}

.main h1 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--gray-900);
}

/* Cards */
.card {
    background: #fff;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 1.5rem;
    margin-bottom: 1rem;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--gray-200);
}

.stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: #fff;
    padding: 1.25rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    text-align: center;
}

.stat-card .number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary);
}

.stat-card .label {
    font-size: 0.875rem;
    color: var(--gray-500);
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
}

th, td {
    padding: 0.75rem 1rem;
    text-align: left;
    border-bottom: 1px solid var(--gray-200);
}

th {
    background: var(--gray-50);
    font-weight: 600;
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    color: var(--gray-500);
}

tr:hover td { background: var(--gray-50); }

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.5rem 1rem;
    border: none;
    border-radius: var(--radius);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.15s;
}

.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); text-decoration: none; }
.btn-danger { background: var(--danger); color: #fff; }
.btn-danger:hover { background: #b91c1c; }
.btn-sm { padding: 0.3rem 0.6rem; font-size: 0.8rem; }
.btn-outline { background: transparent; border: 1px solid var(--gray-300); color: var(--gray-700); }
.btn-outline:hover { background: var(--gray-100); text-decoration: none; }

.actions { display: flex; gap: 0.4rem; }

/* Forms */
.form-group {
    margin-bottom: 1rem;
}

.form-group label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.3rem;
    font-size: 0.875rem;
    color: var(--gray-700);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.6rem 0.8rem;
    border: 1px solid var(--gray-300);
    border-radius: var(--radius);
    font-size: 0.95rem;
    transition: border-color 0.15s;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37,99,235,0.15);
}

.form-group textarea { min-height: 200px; resize: vertical; }

.form-group select[multiple] { min-height: 120px; }

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: normal;
}

.checkbox-label input { width: auto; }

/* Flash Messages */
.flash {
    padding: 0.75rem 1rem;
    border-radius: var(--radius);
    margin-bottom: 1rem;
    font-size: 0.9rem;
}

.flash-success { background: #dcfce7; color: #166534; border: 1px solid #bbf7d0; }
.flash-error { background: #fee2e2; color: #991b1b; border: 1px solid #fecaca; }
.flash-info { background: #dbeafe; color: #1e40af; border: 1px solid #bfdbfe; }

/* Login page */
.login-page {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    background: linear-gradient(135deg, var(--gray-900) 0%, var(--primary-dark) 100%);
}

.login-box {
    background: #fff;
    padding: 2.5rem;
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 400px;
}

.login-box h1 {
    text-align: center;
    margin-bottom: 0.5rem;
    font-size: 1.5rem;
}

.login-box .subtitle {
    text-align: center;
    color: var(--gray-500);
    margin-bottom: 1.5rem;
    font-size: 0.9rem;
}

.login-box .btn { width: 100%; justify-content: center; padding: 0.7rem; }

.login-links {
    text-align: center;
    margin-top: 1rem;
    font-size: 0.85rem;
}

/* Content grid */
.content-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1rem;
}

.content-card {
    background: #fff;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 1.25rem;
    transition: box-shadow 0.15s;
    display: flex;
    flex-direction: column;
}

.content-card:hover { box-shadow: var(--shadow-lg); }

.content-card h3 { margin-bottom: 0.5rem; }

.content-card .meta {
    font-size: 0.8rem;
    color: var(--gray-500);
    margin-top: auto;
    padding-top: 0.75rem;
}

.content-body { line-height: 1.7; }
.content-body h2 { margin: 1.5rem 0 0.75rem; }
.content-body p { margin-bottom: 0.75rem; }

.file-list {
    list-style: none;
    margin-top: 1rem;
}

.file-list li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--gray-200);
}

.file-list li:last-child { border-bottom: none; }

/* Badge */
.badge {
    display: inline-block;
    padding: 0.15rem 0.5rem;
    border-radius: 999px;
    font-size: 0.75rem;
    font-weight: 500;
}

.badge-admin { background: #fef3c7; color: #92400e; }
.badge-user { background: #dbeafe; color: #1e40af; }
.badge-active { background: #dcfce7; color: #166534; }
.badge-inactive { background: #fee2e2; color: #991b1b; }

/* Responsive */
@media (max-width: 768px) {
    .layout { flex-direction: column; }
    .sidebar { width: 100%; }
    .main { padding: 1rem; }
    .stats { grid-template-columns: 1fr; }
}