/* ==================== 全局样式 ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #1890ff;
    --primary-dark: #096dd9;
    --success-color: #52c41a;
    --warning-color: #faad14;
    --danger-color: #f5222d;
    --text-color: #333333;
    --text-secondary: #666666;
    --border-color: #d9d9d9;
    --bg-gray: #f5f5f5;
    --white: #ffffff;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.15);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
    color: var(--text-color);
    background-color: var(--bg-gray);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ==================== 顶部导航栏 ==================== */
.header {
    background-color: var(--white);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
}

.logo h1 {
    font-size: 24px;
    color: var(--primary-color);
    font-weight: 600;
}

.nav ul {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav a {
    text-decoration: none;
    color: var(--text-color);
    font-size: 16px;
    transition: color 0.3s;
    padding: 8px 0;
    border-bottom: 2px solid transparent;
}

.nav a:hover,
.nav a.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

.user-info {
    display: flex;
    align-items: center;
    gap: 15px;
}

.username {
    color: var(--text-secondary);
    font-size: 14px;
}

.logout-btn {
    padding: 6px 16px;
    background-color: var(--primary-color);
    color: var(--white);
    text-decoration: none;
    border-radius: 4px;
    font-size: 14px;
    transition: background-color 0.3s;
}

.logout-btn:hover {
    background-color: var(--primary-dark);
}

/* ==================== 面包屑导航 ==================== */
.breadcrumb {
    background-color: var(--white);
    padding: 15px 0;
    border-bottom: 1px solid var(--border-color);
}

.breadcrumb .container {
    display: flex;
    align-items: center;
    font-size: 14px;
}

.breadcrumb a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s;
}

.breadcrumb a:hover {
    color: var(--primary-dark);
}

.breadcrumb .separator {
    margin: 0 10px;
    color: var(--text-secondary);
}

.breadcrumb .current {
    color: var(--text-color);
}

/* ==================== 页面标题区域（通用） ==================== */
.page-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 30px;
}

.header-left {
    display: flex;
    align-items: center;
}

.header-right {
    text-align: right;
    flex: 1;
}

.header-right h2 {
    font-size: 28px;
    color: var(--text-color);
    margin-bottom: 15px;
}

.exam-info-tags {
    display: flex;
    gap: 10px;
    justify-content: flex-end;
}

.info-tag {
    padding: 6px 15px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 500;
}

.info-tag.difficulty {
    background-color: #fff7e6;
    color: var(--warning-color);
}

.info-tag.category {
    background-color: #e6f7ff;
    color: var(--primary-color);
}

.info-tag.exam-name {
    background-color: #f0f5ff;
    color: #2f54eb;
}

.btn-secondary {
    padding: 10px 20px;
    background-color: var(--white);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    gap: 5px;
}

.btn-secondary:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

/* ==================== 主要内容区域 ==================== */
.main-content {
    flex: 1;
    padding: 40px 0;
}

.page-header {
    text-align: center;
    margin-bottom: 40px;
}

.page-header h2 {
    font-size: 32px;
    color: var(--text-color);
    margin-bottom: 10px;
}

.subtitle {
    font-size: 16px;
    color: var(--text-secondary);
}

/* ==================== 搜索和筛选区域 ==================== */
.filter-section {
    background-color: var(--white);
    padding: 25px;
    border-radius: 8px;
    margin-bottom: 30px;
    box-shadow: var(--shadow);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.search-box {
    display: flex;
    flex: 1;
    min-width: 300px;
}

.search-box input {
    flex: 1;
    padding: 10px 15px;
    border: 1px solid var(--border-color);
    border-radius: 4px 0 0 4px;
    font-size: 14px;
    outline: none;
    transition: border-color 0.3s;
}

.search-box input:focus {
    border-color: var(--primary-color);
}

.search-btn {
    padding: 10px 25px;
    background-color: var(--primary-color);
    color: var(--white);
    border: none;
    border-radius: 0 4px 4px 0;
    cursor: pointer;
    font-size: 14px;
    transition: background-color 0.3s;
}

.search-btn:hover {
    background-color: var(--primary-dark);
}

.filter-box {
    display: flex;
    gap: 15px;
}

.filter-box select {
    padding: 10px 15px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 14px;
    cursor: pointer;
    outline: none;
    background-color: var(--white);
    transition: border-color 0.3s;
    width: 200px;
}

.filter-box select:focus {
    border-color: var(--primary-color);
}

/* ==================== 加载提示 ==================== */
.loading {
    text-align: center;
    padding: 60px 20px;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

.loading p {
    color: var(--text-secondary);
    font-size: 16px;
}

/* ==================== 考试列表 ==================== */
.exam-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 25px;
    margin-bottom: 40px;
}

.exam-card {
    background-color: var(--white);
    border-radius: 8px;
    padding: 25px;
    box-shadow: var(--shadow);
    transition: all 0.3s;
    cursor: pointer;
    border: 2px solid transparent;
}

.exam-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
    border-color: var(--primary-color);
}

.exam-card-header {
    display: flex;
    align-items: flex-start;
    margin-bottom: 15px;
}

.exam-icon {
    width: 60px;
    height: 60px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 30px;
    margin-right: 15px;
    flex-shrink: 0;
}

.exam-icon.music {
    background-color: #fff0f6;
    color: #eb2f96;
}

.exam-icon.language {
    background-color: #e6f7ff;
    color: #1890ff;
}

.exam-icon.math {
    background-color: #f6ffed;
    color: #52c41a;
}

.exam-icon.other {
    background-color: #fff7e6;
    color: #fa8c16;
}

.exam-info {
    flex: 1;
}

.exam-title {
    font-size: 20px;
    font-weight: 600;
    color: var(--text-color);
    margin-bottom: 5px;
}

.exam-category {
    display: inline-block;
    padding: 2px 10px;
    background-color: var(--bg-gray);
    color: var(--text-secondary);
    font-size: 12px;
    border-radius: 3px;
}

.exam-description {
    color: var(--text-secondary);
    font-size: 14px;
    line-height: 1.6;
    margin-bottom: 15px;
}

.exam-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 15px;
    border-top: 1px solid var(--border-color);
}

.exam-stats {
    display: flex;
    gap: 20px;
    font-size: 13px;
    color: var(--text-secondary);
}

.exam-stats span {
    display: flex;
    align-items: center;
    gap: 5px;
}

.difficulty-badge {
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 500;
    display: none; /* 隐藏难度标签 */
}

.difficulty-badge.easy {
    background-color: #f6ffed;
    color: var(--success-color);
}

.difficulty-badge.medium {
    background-color: #fff7e6;
    color: var(--warning-color);
}

.difficulty-badge.hard {
    background-color: #fff1f0;
    color: var(--danger-color);
}

.exam-footer {
    margin-top: 15px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.exam-time {
    font-size: 13px;
    color: var(--text-secondary);
}

.start-btn {
    padding: 8px 20px;
    background-color: var(--primary-color);
    color: var(--white);
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s;
}

.start-btn:hover {
    background-color: var(--primary-dark);
    transform: scale(1.05);
}

/* 无数据提示 */
.no-data {
    text-align: center;
    padding: 80px 20px;
    background-color: var(--white);
    border-radius: 8px;
    box-shadow: var(--shadow);
}

.no-data-icon {
    font-size: 80px;
    color: var(--border-color);
    margin-bottom: 20px;
}

.no-data p {
    color: var(--text-secondary);
    font-size: 16px;
}

/* ==================== 页脚 ==================== */
.footer {
    background-color: #001529;
    color: rgba(255, 255, 255, 0.65);
    padding: 40px 0 20px;
    margin-top: auto;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-bottom: 30px;
}

.footer-section h3 {
    color: var(--white);
    font-size: 16px;
    margin-bottom: 15px;
}

.footer-section p {
    margin-bottom: 8px;
    font-size: 14px;
}

.footer-section a {
    color: rgba(255, 255, 255, 0.65);
    text-decoration: none;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: var(--white);
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-bottom p {
    font-size: 14px;
}

/* ==================== 模态框样式 ==================== */
.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.6);
    animation: fadeIn 0.3s ease;
}

.modal.active {
    display: flex;
    align-items: center;
    justify-content: center;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

.modal-content {
    background-color: var(--white);
    border-radius: 12px;
    width: 90%;
    max-width: 700px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from {
        transform: translateY(50px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 25px 30px;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    font-size: 22px;
    color: var(--text-color);
    margin: 0;
}

.close-btn {
    font-size: 32px;
    color: var(--text-secondary);
    cursor: pointer;
    transition: color 0.3s;
    line-height: 1;
    font-weight: 300;
}

.close-btn:hover {
    color: var(--danger-color);
}

.modal-body {
    padding: 30px;
}

.modal-exam-title {
    font-size: 16px;
    color: var(--text-secondary);
    margin-bottom: 25px;
    text-align: center;
}

.difficulty-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
}

.difficulty-option {
    background-color: var(--white);
    border: 2px solid var(--border-color);
    border-radius: 10px;
    padding: 25px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
}

.difficulty-option:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
    border-color: var(--primary-color);
}

.difficulty-icon {
    font-size: 48px;
    margin-bottom: 15px;
    width: 80px;
    height: 80px;
    margin: 0 auto 15px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.difficulty-icon.beginner {
    background-color: #f6ffed;
    color: var(--success-color);
}

.difficulty-icon.intermediate {
    background-color: #fff7e6;
    color: var(--warning-color);
}

.difficulty-icon.advanced {
    background-color: #fff1f0;
    color: var(--danger-color);
}

.difficulty-option h4 {
    font-size: 20px;
    color: var(--text-color);
    margin: 15px 0 10px;
}

.difficulty-option p {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 15px;
    line-height: 1.5;
}

.difficulty-meta {
    display: flex;
    justify-content: center;
    gap: 15px;
    font-size: 13px;
    color: var(--text-secondary);
    padding-top: 15px;
    border-top: 1px solid var(--border-color);
}

.difficulty-meta span {
    display: flex;
    align-items: center;
    gap: 5px;
}

/* ==================== 响应式设计 ==================== */
@media (max-width: 768px) {
    .header .container {
        flex-direction: column;
        gap: 15px;
    }

    .nav ul {
        gap: 15px;
    }

    .filter-section {
        flex-direction: column;
        align-items: stretch;
    }

    .search-box {
        min-width: 100%;
    }

    .filter-box {
        flex-direction: column;
    }

    .filter-box select {
        width: 100%;
    }

    .exam-list {
        grid-template-columns: 1fr;
    }

    .page-header h2 {
        font-size: 24px;
    }

    .page-header {
        flex-direction: column;
        gap: 15px;
    }

    .exam-info-tags {
        flex-wrap: wrap;
        justify-content: flex-start;
    }
}