body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
    color: #333;
}

header {
    background-color: #333;
    color: #fff;
    padding: 1rem;
}

nav a {
    color: #fff;
    margin-right: 1rem;
    text-decoration: none;
    font-weight: bold;
}

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

main {
    max-width: 800px;
    margin: 2rem auto;
    padding: 1rem;
    background-color: #fff;
    border-radius: 8px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

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

table th, table td {
    border: 1px solid #ddd;
    padding: 8px;
    text-align: left;
}

table th {
    background-color: #f2f2f2;
}

form label {
    margin-right: 0.5rem;
}

form input, form select {
    margin-right: 1rem;
    padding: 0.3rem;
}

button {
    padding: 0.5rem 1rem;
    background-color: #333;
    color: #fff;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}

button:hover {
    background-color: #555;
}

.error {
    color: red;
}