:root {
    --bg-color: #f3f4f6;
    --sidebar-bg: #1f2937;
    --card-bg: #ffffff;
    --text-main: #111827;
    --text-muted: #6b7280;
    --border-color: #e5e7eb;
    --primary: #3b82f6;
    --danger: #ef4444;
}

* { margin: 0; padding: 0; box-sizing: border-box; font-family: 'Inter', sans-serif; }

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

/* Sidebar */
.sidebar {
    width: 250px;
    background-color: var(--sidebar-bg);
    color: white;
    padding: 2rem 1rem;
}

.sidebar h2 {
    font-size: 1.5rem;
    margin-bottom: 2rem;
    text-align: center;
    color: var(--primary);
}

.sidebar nav a {
    display: block;
    color: #d1d5db;
    text-decoration: none;
    padding: 0.75rem 1rem;
    border-radius: 8px;
    margin-bottom: 0.5rem;
    transition: background 0.2s;
}

.sidebar nav a:hover {
    background-color: rgba(255,255,255,0.1);
    color: white;
}

.main-content {
    flex: 1;
    padding: 2rem;
    overflow-y: auto;
}

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

.card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1);
    margin-bottom: 2rem;
}

.stat-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1);
    text-align: center;
}

.stat-card h3 {
    color: var(--text-muted);
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

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

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

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

th {
    color: var(--text-muted);
    font-weight: 600;
}

.btn {
    background: var(--primary);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    cursor: pointer;
    text-decoration: none;
    font-size: 0.875rem;
}

.btn-danger {
    background: var(--danger);
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-group input, .form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 6px;
}

.login-container {
    width: 100%;
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--sidebar-bg);
}

.login-box {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    width: 100%;
    max-width: 400px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.2);
}