body {
    margin: 0;
    padding: 0;
    font-family: 'Microsoft YaHei', sans-serif;
    background-color: #f0f2f5;
    user-select: none;
}
.main-container {
    position: relative;
    min-height: 100vh;
}
.watermark {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 9999;
    background: repeating-linear-gradient(45deg, rgba(0,0,0,0.01) 0px, rgba(0,0,0,0.01) 200px, rgba(0,0,0,0) 200px, rgba(0,0,0,0) 400px);
}
.watermark::after {
    content: "汪老师题库版权，应老师管理工具创建";
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) rotate(-25deg);
    font-size: 28px;
    color: rgba(0,0,0,0.05);
    white-space: nowrap;
    font-weight: bold;
    pointer-events: none;
}
.content {
    max-width: 1000px;
    margin: 0 auto;
    background-color: #ffffff;
    border-radius: 20px;
    padding: 2rem;
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
    position: relative;
    z-index: 1;
}
.page-header {
    text-align: center;
    margin-bottom: 20px;
}
.main-title {
    font-size: 2rem;
    font-weight: bold;
    color: #d93025;
    border-left: none;
    padding-left: 0;
    margin-bottom: 5px;
}
.sub-copyright {
    font-size: 0.9rem;
    color: #555;
    margin-top: 0;
}
h1, h2 {
    color: #d93025;
    border-left: 4px solid #d93025;
    padding-left: 15px;
}
.btn {
    background-color: #f8f9fa;
    color: #d93025;
    border: 1px solid #d93025;
    border-radius: 30px;
    padding: 0.5rem 1.8rem;
    font-weight: bold;
    text-decoration: none;
    display: inline-block;
    cursor: pointer;
    transition: 0.2s;
}
.btn:hover {
    background-color: #e9ecef;
    border-color: #b71c1c;
    color: #b71c1c;
}
.start-btn {
    font-size: 1.2rem;
    margin-top: 20px;
}
.progress-bar {
    background-color: #e9ecef;
    border-radius: 10px;
    height: 8px;
    margin-bottom: 10px;
}
.progress-fill {
    background-color: #d93025;
    width: 0%;
    height: 100%;
    border-radius: 10px;
}
.question-text {
    background-color: #f8f9fa;
    padding: 15px;
    border-radius: 12px;
    margin: 20px 0;
}
.radio-group {
    border: 1px solid #ccc;
    border-radius: 12px;
    padding: 15px 20px;
    margin: 20px 0;
    background-color: #fafafa;
}
.radio-group label {
    margin-right: 30px;
    cursor: pointer;
}
.button-left {
    text-align: left;
    margin-top: 20px;
}
.metrics-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
    margin: 20px 0;
}
.metric-card {
    background-color: #ffffff;
    border-radius: 16px;
    padding: 1rem;
    text-align: center;
    box-shadow: 0 2px 8px rgba(0,0,0,0.05);
    border-top: 3px solid #d93025;
}
.metric-number {
    font-size: 2.2rem;
    font-weight: bold;
    color: #d93025;
}
.dataframe {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
}
.dataframe th {
    background-color: #f8f9fa;
    color: black;
    font-weight: bold;
    padding: 8px;
    text-align: center;
    border-bottom: 2px solid #ddd;
}
.dataframe td {
    padding: 8px;
    text-align: center;
    border-bottom: 1px solid #e9ecef;
}
details {
    margin: 10px 0;
    padding: 10px;
    border: 1px solid #e9ecef;
    border-radius: 8px;
}
.success {
    color: #2e7d32;
}
.advice {
    background-color: #fef2e8;
    padding: 15px;
    border-left: 5px solid #d93025;
}
.button-group {
    display: flex;
    gap: 20px;
    justify-content: center;
    margin: 20px 0;
}
.footnote {
    text-align: center;
    font-size: 0.8rem;
    color: #6c757d;
}
/* 登录页样式（无禁止复制、无水印） */
.login-body {
    user-select: auto !important;
}
.login-body .watermark {
    display: none;
}
.login-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #e8f5e9;
}
.login-card {
    max-width: 400px;
    width: 100%;
    background: white;
    border: 2px solid #2e7d32;
    border-radius: 24px;
    padding: 40px;
    box-shadow: 0 8px 20px rgba(0,0,0,0.1);
}
.login-card h1 {
    color: #2c3e50;
    border-left: 8px solid #2e7d32;
    padding-left: 20px;
    margin-bottom: 1rem;
}
.login-card input {
    width: 100%;
    padding: 12px;
    margin: 10px 0;
    border: 1px solid #ccc;
    border-radius: 8px;
    font-size: 1rem;
    box-sizing: border-box;
}
.login-card .btn {
    background: #2e7d32;
    color: white;
    border: none;
    width: 100%;
    padding: 12px;
    font-size: 1.1rem;
}
.login-card .btn:hover {
    background: #1b5e20;
}
.captcha-box {
    background: #f0f0f0;
    padding: 12px;
    text-align: center;
    font-size: 1.8rem;
    font-weight: bold;
    border-radius: 12px;
    margin: 15px 0;
    letter-spacing: 4px;
}
.refresh-link {
    text-align: right;
    font-size: 0.8rem;
    margin-top: -10px;
    margin-bottom: 10px;
}
.refresh-link a {
    color: #2e7d32;
    cursor: pointer;
    text-decoration: none;
}
.footer-link {
    text-align: center;
    margin-top: 20px;
}
.footer-link a {
    color: #2e7d32;
    text-decoration: none;
}
.error {
    color: #d93025;
    text-align: center;
}
.agreement {
    margin: 15px 0;
    font-size: 0.9rem;
}
/* 底部版权信息 */
.footer-copyright {
    text-align: center;
    font-size: 12px;
    color: #888;
    margin-top: 30px;
    padding-top: 10px;
    border-top: 1px solid #eee;
    clear: both;
}