/* 全局样式 */
body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
}

header {
    background-color: #333;
    color: white;
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header .logo {
    font-size: 1.5rem;
    font-weight: bold;
}

nav ul {
    list-style: none;
    display: flex;
    gap: 1rem;
}

nav a {
    color: white;
    text-decoration: none;
}

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

main {
    padding: 2rem;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 1rem;
}

table, th, td {
    border: 1px solid #ddd;
}

th, td {
    padding: 0.5rem;
    text-align: left;
}

th {
    background-color: #f4f4f4;
}

button {
    padding: 0.5rem 1rem;
    background-color: #333;
    color: white;
    border: none;
    cursor: pointer;
}

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

.login-container {
    max-width: 400px;
    margin: 2rem auto;
    padding: 2rem;
    background-color: white;
    border-radius: 5px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

.error {
    color: red;
}