body {
    font-family: sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
    color: #333;
}
header {
    background: #333;
    color: #fff;
    padding: 1rem 0;
    text-align: center;
}
header h1 {
    margin: 0;
}
header nav a {
    color: #fff;
    text-decoration: none;
    margin: 0 10px;
}
main {
    padding: 20px;
    max-width: 800px;
    margin: 20px auto;
    background: #fff;
    border-radius: 5px;
}
article {
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 1px #eee solid;
}
article:last-child {
    border-bottom: none;
}
footer {
    text-align: center;
    padding: 20px;
    margin-top: 20px;
    color: #777;
}
/* 登录表单样式 */
form div {
    margin-bottom: 10px;
}
form label {
    display: block;
    margin-bottom: 5px;
}
form input[type="text"],
form input[type="password"],
form textarea {
    width: calc(100% - 22px); /* 减去padding和border */
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 3px;
}
form button {
    background: #5cb85c;
    color: white;
    border: none;
    padding: 10px 15px;
    border-radius: 3px;
    cursor: pointer;
}
form button:hover {
    background: #4cae4c;
}
/* 提示消息 */
.alert {
    padding: 10px;
    margin-bottom: 15px;
    border: 1px solid transparent;
    border-radius: 4px;
}
.alert-success {
    color: #3c763d;
    background-color: #dff0d8;
    border-color: #d6e9c6;
}
.alert-danger {
    color: #a94442;
    background-color: #f2dede;
    border-color: #ebccd1;
}
.alert-info {
    color: #31708f;
    background-color: #d9edf7;
    border-color: #bce8f1;
}
.alert-warning {
    color: #8a6d3b;
    background-color: #fcf8e3;
    border-color: #faebcc;
}