:root {
    --primary-color: #4a90e2;
    --secondary-color: #357abd;
    --info-color: #00e1ff;
    --bg-color: #f4f6f9;
    --text-color: #333;
    --sidebar-width: 250px;
    --header-height: 60px;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    margin: 0;
    color: var(--text-color);
    display: flex;
    min-height: 100vh;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background-color: #2c3e50;
    color: #ecf0f1;
    display: flex;
    flex-direction: column;
    position: fixed;
    height: 100%;
    left: 0;
    top: 0;
}

.sidebar-header {
    height: var(--header-height);
    display: flex;
    align-items: center;
    justify_content: center;
    background-color: #1a252f;
    font-size: 1.2rem;
    font-weight: bold;
    padding: 0 20px;
}

.sidebar-menu {
    list-style: none;
    padding: 0;
    margin: 0;
}

.sidebar-menu li a {
    display: block;
    padding: 15px 20px;
    color: #bdc3c7;
    text-decoration: none;
    transition: 0.3s;
    border-left: 4px solid transparent;
}

.sidebar-menu li a:hover,
.sidebar-menu li a.active {
    background-color: #34495e;
    color: #fff;
    border-left-color: var(--primary-color);
}

/* Main Content */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    display: flex;
    flex-direction: column;
}

.header {
    height: var(--header-height);
    background-color: #fff;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 20px;
}

.container {
    padding: 20px;
    flex: 1;
    overflow-y: auto;
}

/* Cards */
.card {
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
    padding: 20px;
    margin-bottom: 20px;
}

.card-header {
    margin-bottom: 15px;
    border-bottom: 1px solid #eee;
    padding-bottom: 10px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.card-title {
    margin: 0;
    font-size: 1.2rem;
    color: #2c3e50;
}

/* Forms */
.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
}

.form-control {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    box-sizing: border-box;
}

.btn {
    padding: 10px 20px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
    font-size: 0.9rem;
    color: #fff;
}

.btn-primary {
    background-color: var(--primary-color);
}

.btn-primary:hover {
    background-color: var(--secondary-color);
}

.btn-danger {
    background-color: #e74c3c;
}

.btn-success {
    background-color: #2ecc71;
}

.btn-sm {
    padding: 5px 10px;
    font-size: 0.8rem;
}

.btn-secondary {
    background-color: #95a5a6;
    color: #fff;
}

.btn-secondary:hover {
    background-color: #7f8c8d;
}

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

.table th,
.table td {
    padding: 12px;
    text-align: left;
    border-bottom: 1px solid #eee;
}

.table th {
    background-color: #f8f9fa;
    font-weight: 600;
}

.alert {
    padding: 15px;
    margin-bottom: 20px;
    border-radius: 4px;
}

.alert-success {
    background-color: #d4edda;
    color: #155724;
}

.alert-danger {
    background-color: #f8d7da;
    color: #721c24;
}

/* Stat Cards */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: #fff;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
    text-align: center;
}

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

.stat-label {
    color: #7f8c8d;
}

/* Login Page Override */
body.login-page {
    justify-content: center;
    align-items: center;
    background: #e9ecef;
}

.login-box {
    width: 350px;
    background: #fff;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.btn-info {
    background-color: var(--info-color);
}