body {
    font-family: Arial, sans-serif;
    margin: 20px;
    background-color: #f4f4f4;
}

h2, h3 {
    color: #333;
}

nav a {
    margin-right: 10px;
    text-decoration: none;
    color: #0066cc;
}

nav a:hover {
    text-decoration: underline;
}

form {
    background: #fff;
    padding: 20px;
    border: 1px solid #ddd;
    max-width: 500px;
    margin-bottom: 20px;
}

input[type="text"],
input[type="password"],
input[type="number"],
select {
    width: 100%;
    padding: 8px;
    margin-top: 4px;
    margin-bottom: 12px;
    border: 1px solid #ccc;
    box-sizing: border-box;
}

input[type="submit"] {
    padding: 10px 15px;
    background: #0066cc;
    border: none;
    color: #fff;
    cursor: pointer;
}

input[type="submit"]:hover {
    background: #004999;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 20px;
    background: #fff;
}

table th, table td {
    border: 1px solid #ccc;
    text-align: center;
    padding: 10px;
}

.error {
    color: red;
}

.success {
    color: green;
}

/* Mobile responsiveness */
@media (max-width: 600px) {
    body {
        margin: 10px;
    }
    form {
        width: 100%;
    }
}