body {
    margin: 0;
    font-family: Arial, sans-serif;
}
.sidebar {
    width: 200px;
    background: #333;
    color: #fff;
    position: fixed;
    height: 100%;
    padding: 20px;
}
.sidebar h2 {
    color: #fff;
    font-size: 18px;
}
.sidebar ul {
    list-style: none;
    padding: 0;
}
.sidebar ul li {
    margin: 10px 0;
}
.sidebar ul li a {
    color: #ddd;
    text-decoration: none;
}
.sidebar ul li a:hover {
    color: #fff;
}
.main-content {
    margin-left: 240px;
    padding: 20px;
}
table {
    width: 100%;
    border-collapse: collapse;
}
table th, table td {
    border: 1px solid #ccc;
    padding: 8px;
    text-align: left;
}
table th {
    background: #f0f0f0;
}
.btn {
    display: inline-block;
    padding: 6px 12px;
    background: #007bff;
    color: #fff;
    text-decoration: none;
    border-radius: 4px;
    margin: 5px 0;
}
.error { color: red; }
.success { color: green; }
.login-container {
    max-width: 300px;
    margin: 100px auto;
}