/* ========================================
   体育单招在线学习 - 运动风格主题
   体育元素 · 大气漂亮 · 全设备自适应
   ======================================== */

:root {
    /* 运动主题色系 - 活力蓝橙搭配 */
    --primary: #0066cc;
    --primary-dark: #004999;
    --primary-light: #e6f2ff;
    --accent: #ff6b35;
    --accent-dark: #e8541a;
    --accent-light: #fff0eb;
    --success: #00b865;
    --warning: #ffb800;
    --danger: #ff3b30;
    --info: #00b8d9;
    --bg-light: #f5f7fa;
    --bg-dark: #0a1628;
    --text-dark: #1a2332;
    --text-muted: #6b7a8f;
    --border-color: #e3e8ef;
    --shadow: 0 2px 8px rgba(0,102,204,0.06), 0 1px 3px rgba(0,0,0,0.04);
    --shadow-lg: 0 12px 32px rgba(0,102,204,0.12), 0 4px 12px rgba(0,0,0,0.06);
    --shadow-glow: 0 0 24px rgba(255,107,53,0.2);
    --radius: 16px;
    --radius-sm: 10px;
    --radius-lg: 24px;
    --bottom-nav-height: 64px;
    --nav-height: 62px;
    --gradient-primary: linear-gradient(135deg, #0066cc 0%, #004999 100%);
    --gradient-accent: linear-gradient(135deg, #ff6b35 0%, #e8541a 100%);
    --gradient-hero: linear-gradient(135deg, #0a1628 0%, #004999 40%, #0066cc 70%, #ff6b35 130%);
    --gradient-sport: linear-gradient(135deg, #0066cc 0%, #00b8d9 50%, #00b865 100%);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    background: var(--bg-light);
    color: var(--text-dark);
    padding-bottom: var(--bottom-nav-height);
    overflow-x: hidden;
}

@media (min-width: 992px) {
    body { padding-bottom: 0; }
}

/* ========== 运动风导航栏 ========== */
.navbar-dark.bg-primary {
    background: linear-gradient(135deg, #0a1628 0%, #004999 60%, #0066cc 100%) !important;
    min-height: var(--nav-height);
    box-shadow: 0 2px 20px rgba(0,0,0,0.15);
    border-bottom: 3px solid var(--accent);
}

.navbar-brand {
    display: flex;
    align-items: center;
    gap: 8px;
}

.navbar-brand .site-name {
    font-weight: 800;
    font-size: 1.15rem;
    letter-spacing: 0.5px;
    background: linear-gradient(90deg, #fff, #ffd700);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.navbar-brand i {
    font-size: 1.4rem;
    color: var(--accent);
    filter: drop-shadow(0 2px 4px rgba(255,107,53,0.4));
}

.navbar .nav-link {
    font-size: 0.92rem;
    padding: 0.5rem 0.9rem;
    border-radius: var(--radius-sm);
    margin: 0 2px;
    transition: all 0.25s;
    position: relative;
    color: rgba(255,255,255,0.85);
}

.navbar .nav-link:hover {
    background: rgba(255,255,255,0.1);
    color: #fff;
    transform: translateY(-1px);
}

.navbar .nav-link.active {
    background: rgba(255,107,53,0.2);
    color: #fff;
    font-weight: 600;
}

.navbar .nav-link.active::after {
    content: '';
    position: absolute;
    bottom: 2px;
    left: 50%;
    transform: translateX(-50%);
    width: 20px;
    height: 3px;
    background: var(--accent);
    border-radius: 2px;
}

/* ========== 运动风Hero Section ========== */
.hero-section {
    background: var(--gradient-hero);
    position: relative;
    overflow: hidden;
    border-radius: 0 0 28px 28px;
}

/* 跑道线条装饰 */
.hero-section::before {
    content: '';
    position: absolute;
    top: -30%;
    right: -15%;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(255,107,53,0.15) 0%, transparent 70%);
    border-radius: 50%;
}

/* 体育场弧线装饰 */
.hero-section::after {
    content: '';
    position: absolute;
    bottom: -40%;
    left: -20%;
    width: 600px;
    height: 600px;
    border: 2px solid rgba(255,255,255,0.06);
    border-radius: 50%;
}

.hero-section .container {
    position: relative;
    z-index: 1;
}

.hero-section h1 {
    text-shadow: 0 2px 12px rgba(0,0,0,0.3);
    letter-spacing: 1px;
}

.hero-section .lead {
    text-shadow: 0 1px 6px rgba(0,0,0,0.2);
}

/* 运动图标装饰 */
.hero-sport-icons {
    position: absolute;
    top: 50%;
    right: 5%;
    transform: translateY(-50%);
    display: none;
    flex-direction: column;
    gap: 20px;
    opacity: 0.08;
    z-index: 0;
}

@media (min-width: 768px) {
    .hero-sport-icons { display: flex; }
}

.hero-sport-icons i {
    font-size: 3rem;
    color: #fff;
    animation: float-icon 4s ease-in-out infinite;
}

.hero-sport-icons i:nth-child(2) { animation-delay: 1s; }
.hero-sport-icons i:nth-child(3) { animation-delay: 2s; }
.hero-sport-icons i:nth-child(4) { animation-delay: 3s; }

@keyframes float-icon {
    0%,100% { transform: translateY(0) rotate(-5deg); }
    50% { transform: translateY(-15px) rotate(5deg); }
}

/* ========== 统计卡片 ========== */
.stat-card {
    background: white;
    border-radius: var(--radius);
    padding: 1.5rem 1rem;
    box-shadow: var(--shadow);
    transition: all 0.25s;
    position: relative;
    overflow: hidden;
    border-top: 3px solid transparent;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 3px;
    background: var(--gradient-accent);
    transform: scaleX(0);
    transition: transform 0.3s;
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.stat-card:hover::before {
    transform: scaleX(1);
}

.stat-number {
    font-size: 2.2rem;
    font-weight: 900;
    line-height: 1;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-top: 0.3rem;
    font-weight: 500;
}

/* ========== Section标题 ========== */
.section-title {
    font-size: 1.3rem;
    font-weight: 800;
    margin-bottom: 1rem;
    padding-bottom: 0.6rem;
    border-bottom: 3px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 8px;
}

.section-title::before {
    content: '';
    display: inline-block;
    width: 4px;
    height: 22px;
    background: var(--gradient-accent);
    border-radius: 2px;
}

/* ========== 科目卡片 - 运动配色 ========== */
.subject-card {
    border-radius: var(--radius);
    padding: 1.5rem 1rem;
    text-align: center;
    color: white;
    transition: all 0.3s;
    min-height: 130px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.subject-card::after {
    content: '';
    position: absolute;
    top: -50%;
    right: -30%;
    width: 100px;
    height: 100px;
    background: rgba(255,255,255,0.08);
    border-radius: 50%;
    transition: all 0.4s;
}

.subject-card:hover {
    transform: translateY(-5px) scale(1.02);
    box-shadow: 0 16px 40px rgba(0,0,0,0.15);
    color: white;
}

.subject-card:hover::after {
    transform: scale(1.5);
}

.subject-chinese { background: linear-gradient(135deg, #0066cc, #004999); }
.subject-math { background: linear-gradient(135deg, #00b865, #009954); }
.subject-english { background: linear-gradient(135deg, #00b8d9, #0099b8); }
.subject-politics { background: linear-gradient(135deg, #ff6b35, #e8541a); }

.subject-icon {
    font-size: 2.2rem;
    margin-bottom: 0.5rem;
    filter: drop-shadow(0 2px 6px rgba(0,0,0,0.2));
}

.subject-name {
    font-size: 1.15rem;
    font-weight: 800;
    letter-spacing: 0.5px;
}

.subject-count {
    font-size: 0.8rem;
    opacity: 0.85;
    margin-top: 0.2rem;
}

/* ========== 功能卡片 ========== */
.feature-card {
    background: white;
    border-radius: var(--radius);
    padding: 1.3rem;
    text-align: center;
    box-shadow: var(--shadow);
    transition: all 0.25s;
    height: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    border: 1px solid transparent;
    position: relative;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-light);
}

.feature-card i {
    font-size: 2rem;
    margin-bottom: 0.5rem;
    transition: transform 0.3s;
}

.feature-card:hover i {
    transform: scale(1.15) rotate(-5deg);
}

.feature-card span {
    font-weight: 700;
    display: block;
    font-size: 0.95rem;
}

.feature-card small {
    color: var(--text-muted);
    margin-top: 0.2rem;
    font-size: 0.78rem;
}

a.feature-card-link { text-decoration: none; color: var(--text-dark); }

/* ========== 刷题模式选择 ========== */
.mode-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 1.5rem 1rem;
    border-radius: var(--radius);
    background: white;
    box-shadow: var(--shadow);
    text-decoration: none;
    color: var(--text-dark);
    transition: all 0.25s;
    min-height: 110px;
    border: 2px solid transparent;
    position: relative;
    overflow: hidden;
}

.mode-card::before {
    content: '';
    position: absolute;
    bottom: 0; left: 0;
    width: 100%;
    height: 3px;
    background: var(--gradient-accent);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.3s;
}

.mode-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
    color: var(--primary);
    border-color: var(--primary-light);
}

.mode-card:hover::before {
    transform: scaleX(1);
}

.mode-card i {
    font-size: 1.8rem;
    margin-bottom: 0.4rem;
}

.mode-card span {
    font-weight: 700;
    font-size: 0.95rem;
}

/* ========== 科目练习卡片 ========== */
.subject-practice-card {
    display: block;
    padding: 1rem;
    border-radius: var(--radius);
    background: white;
    box-shadow: var(--shadow);
    text-decoration: none;
    color: var(--text-dark);
    transition: all 0.25s;
    border-left: 4px solid transparent;
}

.subject-practice-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    color: var(--text-dark);
}

.subject-icon-lg {
    width: 52px;
    height: 52px;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
    flex-shrink: 0;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.subject-bg-chinese { background: linear-gradient(135deg, #0066cc, #004999); }
.subject-bg-math { background: linear-gradient(135deg, #00b865, #009954); }
.subject-bg-english { background: linear-gradient(135deg, #00b8d9, #0099b8); }
.subject-bg-politics { background: linear-gradient(135deg, #ff6b35, #e8541a); }

/* ========== 知识点卡片 ========== */
.kp-card {
    display: block;
    padding: 0.8rem 1rem;
    border-radius: var(--radius);
    background: white;
    border: 1px solid #e5e7eb;
    text-decoration: none;
    color: var(--text-dark);
    transition: all 0.2s;
    min-height: 48px;
}

.kp-card:hover {
    border-color: var(--accent);
    background: var(--accent-light);
    color: var(--accent-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow);
}

.kp-card:active {
    transform: translateY(0);
    background: var(--accent-light);
}

.kp-name {
    font-size: 0.9rem;
    font-weight: 500;
}

@media (max-width: 768px) {
    .kp-card {
        padding: 0.7rem 0.8rem;
        min-height: 44px;
    }
    .kp-name {
        font-size: 0.85rem;
    }
}

/* ========== 快捷链接 ========== */
.quick-link-card {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0.8rem;
    border-radius: var(--radius);
    background: white;
    box-shadow: var(--shadow);
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 600;
    transition: all 0.2s;
}

.quick-link-card:hover {
    background: var(--primary-light);
    color: var(--primary);
}

/* ========== 试卷卡片 ========== */
a.paper-card-link { text-decoration: none; color: var(--text-dark); }

.paper-card {
    background: white;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    overflow: hidden;
    transition: all 0.25s;
    border-left: 4px solid var(--primary);
}

.paper-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.predict-card {
    border-left-color: var(--accent);
}

.paper-card-body {
    padding: 1rem 1.2rem;
}

/* ========== 题目卡片 ========== */
.question-card {
    background: white;
    border-radius: var(--radius);
    padding: 1.2rem;
    margin-bottom: 1rem;
    box-shadow: var(--shadow);
}

.question-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.8rem;
}

.question-num {
    background: var(--gradient-primary);
    color: white;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.85rem;
    font-weight: 700;
    flex-shrink: 0;
    box-shadow: 0 2px 8px rgba(0,102,204,0.3);
}

.question-text {
    font-size: 1.05rem;
    line-height: 1.7;
    margin-bottom: 1rem;
    font-weight: 500;
}

.question-options {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.option-item {
    display: flex;
    align-items: center;
    padding: 0.7rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all 0.15s;
}

.option-item:hover {
    border-color: var(--primary);
    background: var(--primary-light);
}

.option-item.selected {
    border-color: var(--primary);
    background: var(--primary-light);
}

.option-item.correct {
    border-color: var(--success);
    background: #d4f7e3;
}

.option-item.wrong {
    border-color: var(--danger);
    background: #ffe0de;
}

.option-letter {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    background: var(--bg-light);
    font-weight: 700;
    margin-right: 0.7rem;
    flex-shrink: 0;
    font-size: 0.9rem;
}

.option-item.selected .option-letter {
    background: var(--primary);
    color: white;
}

.option-item.correct .option-letter {
    background: var(--success);
    color: white;
}

.option-item.wrong .option-letter {
    background: var(--danger);
    color: white;
}

.option-text {
    flex: 1;
    line-height: 1.5;
}

.question-answer {
    margin-top: 0.8rem;
}

.answer-box {
    background: var(--bg-light);
    border-radius: var(--radius-sm);
    padding: 0.8rem 1rem;
    border-left: 4px solid var(--accent);
}

.answer-correct {
    color: var(--success);
    font-weight: 700;
    margin-bottom: 0.3rem;
}

.answer-analysis {
    color: var(--text-dark);
    line-height: 1.7;
    font-size: 0.95rem;
}

.fav-btn {
    margin-left: auto;
    padding: 0;
    text-decoration: none;
}

/* ========== 词汇卡片 ========== */
.vocab-card {
    background: white;
    border-radius: var(--radius);
    margin-bottom: 0.8rem;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: box-shadow 0.2s;
}

.vocab-card:hover {
    box-shadow: var(--shadow-lg);
}

.vocab-word-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.2rem;
    cursor: pointer;
    transition: background 0.15s;
}

.vocab-word-row:hover {
    background: var(--bg-light);
}

.vocab-word {
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--primary);
}

.vocab-phonetic {
    font-size: 0.85rem;
}

.vocab-meaning-toggle {
    display: flex;
    align-items: center;
    gap: 0.3rem;
}

.vocab-detail {
    padding: 0 1.2rem;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
}

.vocab-card.show-meaning .vocab-detail {
    max-height: 300px;
    padding: 0 1.2rem 1rem;
}

.vocab-example {
    color: var(--info);
    font-style: italic;
    margin-bottom: 0.3rem;
}

.vocab-example-trans {
    margin-bottom: 0.5rem;
}

.vocab-locked {
    background: var(--bg-light);
    border-radius: var(--radius);
    padding: 2rem 1rem;
    margin-top: 1rem;
}

/* ========== 词汇进度卡片 ========== */
.vocab-progress-card {
    background: white;
    border-radius: var(--radius);
    padding: 1.2rem;
    box-shadow: var(--shadow);
}

/* ========== 词汇筛选 ========== */
.vocab-filter .badge {
    padding: 0.5rem 0.8rem;
    cursor: pointer;
    text-decoration: none;
}

/* ========== 资讯样式 ========== */
.news-filter .badge {
    padding: 0.5rem 0.8rem;
    cursor: pointer;
    text-decoration: none;
}

.news-title {
    font-weight: 600;
    color: var(--text-dark);
}

.list-group-item:hover .news-title {
    color: var(--primary);
}

.news-detail h2 {
    font-weight: 800;
}

.news-content {
    font-size: 1.05rem;
    line-height: 1.8;
    color: var(--text-dark);
}
.news-content h3 { font-size: 1.4rem; font-weight: 700; margin: 1.5rem 0 0.8rem; color: var(--primary-dark); }
.news-content h4 { font-size: 1.2rem; font-weight: 600; margin: 1.2rem 0 0.6rem; color: var(--text-dark); }
.news-content p { margin-bottom: 0.8rem; }
.news-content ul, .news-content ol { margin-bottom: 0.8rem; padding-left: 1.5rem; }
.news-content li { margin-bottom: 0.3rem; }
.news-content table { width: 100%; margin: 1rem 0; font-size: 0.95rem; }
.news-content .table th { background: var(--primary-light); font-weight: 600; }
.news-content a { color: var(--primary); text-decoration: none; }
.news-content a:hover { text-decoration: underline; }
.news-content .alert { margin: 1rem 0; padding: 0.8rem 1.2rem; border-radius: var(--radius-sm); }
.news-content strong { font-weight: 700; }

/* ========== 个人中心 ========== */
.profile-header-card {
    background: white;
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
}

.profile-avatar {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: var(--primary-light);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: var(--primary);
}

.profile-tabs .nav-link {
    color: var(--text-muted);
    font-weight: 600;
}

.profile-tabs .nav-link.active {
    color: var(--primary);
}

.stat-card-mini {
    background: white;
    border-radius: var(--radius);
    padding: 1rem;
    text-align: center;
    box-shadow: var(--shadow);
}

.stat-card-mini .stat-icon {
    font-size: 1.5rem;
    margin-bottom: 0.3rem;
}

.stat-card-mini .stat-value {
    font-size: 1.5rem;
    font-weight: 800;
}

.stat-card-mini .stat-label {
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* ========== 认证页面 ========== */
.auth-body {
    background: var(--gradient-hero);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
}

.auth-wrapper {
    width: 100%;
    max-width: 420px;
}

.auth-card {
    background: white;
    border-radius: 24px;
    padding: 2.5rem 2rem;
    box-shadow: 0 20px 60px rgba(0,0,0,0.25);
}

.auth-header {
    text-align: center;
    margin-bottom: 2rem;
}

.auth-logo {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 70px;
    height: 70px;
    border-radius: 50%;
    background: var(--primary-light);
    color: var(--primary);
    font-size: 2rem;
    margin-bottom: 1rem;
    text-decoration: none;
}

.auth-header h2 {
    font-weight: 800;
    font-size: 1.4rem;
    margin-bottom: 0.3rem;
}

.alert-sm {
    padding: 0.5rem 0.8rem;
    font-size: 0.9rem;
}

/* ========== 底部导航 - 运动风格 ========== */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: var(--bottom-nav-height);
    background: white;
    border-top: 1px solid var(--border-color);
    display: flex;
    z-index: 1050;
    box-shadow: 0 -4px 20px rgba(0,0,0,0.06);
}

.bottom-nav a {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    color: var(--text-muted);
    font-size: 0.62rem;
    gap: 2px;
    transition: all 0.2s;
    position: relative;
}

.bottom-nav a i {
    font-size: 1.35rem;
    transition: transform 0.2s;
}

.bottom-nav a.active {
    color: var(--primary);
    font-weight: 600;
}

.bottom-nav a.active i {
    transform: translateY(-2px) scale(1.1);
}

.bottom-nav a.active::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 30px;
    height: 3px;
    background: var(--gradient-accent);
    border-radius: 0 0 3px 3px;
}

/* ========== 底部 ========== */
.site-footer {
    background: var(--bg-dark);
    color: #8ba3b8;
    padding: 2.5rem 0 1.5rem;
}

.site-footer a {
    text-decoration: none;
}

/* ========== 运动风按钮 ========== */
.btn-primary {
    background: var(--gradient-primary);
    border: none;
    font-weight: 600;
    transition: all 0.25s;
    box-shadow: 0 4px 12px rgba(0,102,204,0.25);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0,102,204,0.35);
}

.btn-accent {
    background: var(--gradient-accent);
    border: none;
    color: white;
    font-weight: 600;
    transition: all 0.25s;
    box-shadow: 0 4px 12px rgba(255,107,53,0.25);
}

.btn-accent:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(255,107,53,0.35);
    color: white;
}

/* ========== 运动徽章 ========== */
.badge.bg-primary {
    background: var(--gradient-primary) !important;
}

.badge.bg-accent {
    background: var(--gradient-accent) !important;
}

/* ========== 响应式 - 手机 ========== */
@media (max-width: 576px) {
    .hero-section {
        border-radius: 0 0 20px 20px;
    }
    .hero-section h1 {
        font-size: 1.5rem;
    }
    .hero-section .lead {
        font-size: 0.9rem;
    }
    .stat-number {
        font-size: 1.6rem;
    }
    .stat-card {
        padding: 1rem 0.6rem;
    }
    .section-title {
        font-size: 1.1rem;
    }
    .question-text {
        font-size: 0.98rem;
    }
    .vocab-word {
        font-size: 1rem;
    }
    .auth-card {
        padding: 1.5rem 1.2rem;
    }
    .subject-card {
        min-height: 100px;
        padding: 1rem 0.5rem;
    }
    .subject-icon {
        font-size: 1.8rem;
    }
    .subject-name {
        font-size: 1rem;
    }
    .feature-card {
        padding: 1rem 0.5rem;
    }
    .feature-card i {
        font-size: 1.6rem;
    }
    .feature-card span {
        font-size: 0.85rem;
    }
    .feature-card small {
        font-size: 0.7rem;
    }
    .navbar-brand .site-name {
        font-size: 1rem;
    }
    .mode-card {
        min-height: 90px;
        padding: 1rem 0.5rem;
    }
    .mode-card i {
        font-size: 1.5rem;
    }
    .mode-card span {
        font-size: 0.85rem;
    }
    .option-item {
        padding: 0.6rem 0.8rem;
    }
    .option-text {
        font-size: 0.92rem;
    }
}

/* ========== 响应式 - 平板 ========== */
@media (min-width: 577px) and (max-width: 991px) {
    .hero-section h1 {
        font-size: 1.8rem;
    }
    .stat-number {
        font-size: 1.8rem;
    }
}

/* ========== 响应式 - 桌面 ========== */
@media (min-width: 992px) {
    .hero-section h1 {
        font-size: 2.2rem;
    }
}

/* ========== 加载动画 ========== */
.loading {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid var(--border-color);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
}

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

/* ========== 滚动条美化 ========== */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

::-webkit-scrollbar-track {
    background: var(--bg-light);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* ========== 运动风装饰元素 ========== */
.sport-divider {
    display: flex;
    align-items: center;
    gap: 12px;
    margin: 1.5rem 0;
}

.sport-divider::before,
.sport-divider::after {
    content: '';
    flex: 1;
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--border-color), transparent);
}

.sport-divider i {
    color: var(--accent);
    font-size: 1.2rem;
}

/* 运动场跑道线 */
.track-line {
    height: 4px;
    background: linear-gradient(90deg, 
        var(--primary) 0%, 
        var(--primary) 30%, 
        var(--accent) 30%, 
        var(--accent) 60%, 
        var(--success) 60%, 
        var(--success) 100%);
    border-radius: 2px;
    margin: 1rem 0;
}

/* 奖牌样式 */
.medal-badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 3px 10px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 700;
}

.medal-gold { background: linear-gradient(135deg, #ffd700, #ffa500); color: #fff; }
.medal-silver { background: linear-gradient(135deg, #c0c0c0, #a8a8a8); color: #fff; }
.medal-bronze { background: linear-gradient(135deg, #cd7f32, #b87333); color: #fff; }

/* 动画类 */
.fade-in-up {
    animation: fadeInUp 0.5s ease-out;
}

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.pulse-glow {
    animation: pulseGlow 2s ease-in-out infinite;
}

@keyframes pulseGlow {
    0%,100% { box-shadow: 0 0 0 0 rgba(255,107,53,0.4); }
    50% { box-shadow: 0 0 0 12px rgba(255,107,53,0); }
}

/* ========== 数学公式印刷体样式 ========== */

/* MathJax渲染容器 */
.MathJax, .MathJax_Display {
    font-size: 1.05em !important;
}

/* 兜底渲染的行内数学公式 */
.math-inline {
    font-family: 'Cambria Math', 'Latin Modern Math', 'STIX Two Math', 'Times New Roman', serif;
    font-style: italic;
    font-size: 1.05em;
    color: #1a2332;
    white-space: nowrap;
    padding: 0 1px;
}

/* 兜底渲染的块级数学公式 */
.math-display {
    font-family: 'Cambria Math', 'Latin Modern Math', 'STIX Two Math', 'Times New Roman', serif;
    font-style: italic;
    font-size: 1.15em;
    color: #1a2332;
    text-align: center;
    margin: 0.5em 0;
    padding: 0.5em;
    display: block;
}

/* 题目和选项中的数学变量用斜体印刷体 */
.question-text .math-inline,
.option-text .math-inline,
.answer-analysis .math-inline,
.answer-correct .math-inline {
    font-family: 'Cambria Math', 'Latin Modern Math', 'STIX Two Math', 'Times New Roman', serif;
    font-style: italic;
    font-weight: 500;
}

/* 数学公式中的数字和运算符用正体 */
.math-inline .math-num,
.math-display .math-num {
    font-style: normal;
    font-weight: 400;
}

/* MathJax CHTML渲染样式微调 */
mjx-container {
    font-size: 1.05em !important;
}

mjx-container[display="true"] {
    margin: 0.5em 0 !important;
    text-align: center !important;
}

/* 移动端数学公式适配 */
@media (max-width: 576px) {
    .math-inline {
        font-size: 1em;
    }
    .math-display {
        font-size: 1.05em;
        overflow-x: auto;
    }
    mjx-container {
        font-size: 1em !important;
    }
    /* 防止公式溢出 */
    .question-text, .option-text {
        overflow-wrap: break-word;
        word-wrap: break-word;
    }
}