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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f9f9f9;
    margin: 0;
    padding: 0;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

header {
    background-color: var(--secondary);
    color: white;
    padding: 1rem 0;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

header h1 {
    margin: 0;
    padding: 10px 0;
}

nav ul {
    display: flex;
    list-style: none;
    padding: 0;
    margin: 0;
}

nav ul li {
    margin-right: 20px;
}

nav ul li a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

nav ul li a:hover {
    color: var(--primary);
}

main {
    padding: 2rem 0;
}

.row {
    display: flex;
    flex-wrap: wrap;
    margin: 0 -15px;
}

.col {
    flex: 1;
    padding: 0 15px;
    min-width: 300px;
}

.btn {
    display: inline-block;
    padding: 8px 16px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    text-decoration: none;
    font-size: 14px;
    transition: background 0.3s;
}

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

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

.btn-danger:hover {
    background: #c0392b;
}

.form-group {
    margin-bottom: 20px;
}

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

.form-control {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 16px;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
}

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

table th {
    background-color: var(--secondary);
    color: white;
}

table tr:hover {
    background-color: #f5f5f5;
}

footer {
    text-align: center;
    padding: 20px 0;
    margin-top: 20px;
    background-color: var(--secondary);
    color: white;
}

.alert {
    padding: 15px;
    margin: 20px 0;
    border-radius: 4px;
}

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

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

.login-container {
    max-width: 400px;
    margin: 100px auto;
    padding: 20px;
    background: white;
    border-radius: 8px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}