:root {
    --primary: #3498db;
    --secondary: #2c3e50;
    --success: #2ecc71;
    --danger: #e74c3c;
    --warning: #f39c12;
    --light: #ecf0f1;
    --dark: #34495e;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #f5f7fa;
    color: #333;
}

.container {
    display: grid;
    grid-template-areas: 
        "header header"
        "sidebar content";
    grid-template-rows: auto 1fr;
    grid-template-columns: 250px 1fr;
    min-height: 100vh;
}

.header {
    grid-area: header;
    background-color: var(--secondary);
    color: white;
    padding: 15px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.header h1 {
    font-size: 1.5rem;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 15px;
}

.sidebar {
    grid-area: sidebar;
    background-color: var(--dark);
    color: white;
    padding: 20px 0;
}

.menu {
    list-style: none;
}

.menu-item {
    border-left: 4px solid transparent;
    transition: all 0.3s;
}

.menu-item:hover {
    background-color: rgba(255, 255, 255, 0.1);
    border-left: 4px solid var(--primary);
}

.menu-item a {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px 20px;
    color: white;
    text-decoration: none;
    transition: all 0.3s;
}

.menu-item.active {
    background-color: rgba(255, 255, 255, 0.1);
    border-left: 4px solid var(--primary);
}

.main-content {
    grid-area: content;
    padding: 20px;
    background-color: white;
}

.btn {
    padding: 8px 15px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 600;
    transition: all 0.3s;
    text-decoration: none;
    display: inline-block;
    text-align: center;
}

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

.btn-primary:hover {
    background-color: #2980b9;
}

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

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

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

.btn-sm {
    padding: 5px 10px;
    font-size: 12px;
}

.form-container {
    background-color: var(--light);
    padding: 20px;
    border-radius: 5px;
    margin-bottom: 20px;
}

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

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: 600;
}

.form-group input, .form-group select, .form-group textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 5px;
    font-size: 14px;
}

.form-row {
    display: flex;
    gap: 15px;
    margin-bottom: 15px;
}

.form-field {
    flex: 1;
}

.table-container {
    overflow-x: auto;
    margin-top: 20px;
}

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

th, td {
    padding: 12px 15px;
    text-align: left;
    border-bottom: 1px solid #ddd;
}

th {
    background-color: var(--light);
    font-weight: 600;
}

tr:hover {
    background-color: #f9f9f9;
}

.alert {
    padding: 10px 15px;
    border-radius: 5px;
    margin-bottom: 15px;
}

.alert-success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.alert-danger {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.login-container {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
}

.login-form {
    background: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    width: 100%;
    max-width: 400px;
}

.login-form h2 {
    text-align: center;
    margin-bottom: 20px;
    color: var(--secondary);
}

.section-title {
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--light);
    color: var(--secondary);
}

.hidden {
    display: none;
}

@media (max-width: 768px) {
    .container {
        grid-template-areas: 
            "header"
            "content";
        grid-template-columns: 1fr;
    }
    
    .sidebar {
        display: none;
    }
    
    .form-row {
        flex-direction: column;
    }
}

.info-box {
    background: #f8f9fa;
    border-left: 4px solid #007bff;
    padding: 15px;
    margin: 20px 0;
    border-radius: 4px;
}

.info-box h4 {
    margin-top: 0;
    color: #007bff;
}

.text-center {
    text-align: center;
}

.btn-sm {
    padding: 5px 10px;
    font-size: 12px;
}