/* ========================================
   薛老师编程网校 - W3Cschool风格样式 v3
   ======================================== */

:root {
    --primary: #ff6b00;
    --primary-dark: #e55a00;
    --blue: #4a90d9;
    --secondary: #4a90d9;
    --success: #52c41a;
    --warning: #faad14;
    --danger: #f5222d;
    --text-primary: #333;
    --text-secondary: #666;
    --text-muted: #999;
    --bg-body: #f5f5f5;
    --bg-card: #fff;
    --bg-sidebar: #fff;
    --border-color: #e8e8e8;
    --border-light: #f0f0f0;
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.08);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.12);
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --transition: all 0.3s ease;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background: var(--bg-body);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

a { text-decoration: none; color: inherit; transition: var(--transition); }
ul { list-style: none; }

.container { max-width: 1400px; margin: 0 auto; padding: 0 20px; }

/* ===== 顶部导航 ===== */
.site-header {
    background: #fff;
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-top {
    border-bottom: 1px solid var(--border-light);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
    gap: 20px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-shrink: 0;
}

.logo-icon {
    width: 40px; height: 40px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    border-radius: 10px;
    display: flex; align-items: center; justify-content: center;
    font-size: 1.4rem;
}

.logo-text { display: flex; flex-direction: column; }
.logo-name { font-size: 1.2rem; font-weight: 700; color: var(--text-primary); }
.logo-slogan { font-size: 0.7rem; color: var(--text-muted); }

.search-box { flex: 1; max-width: 500px; }
.search-box form { display: flex; position: relative; }
.search-box input {
    width: 100%; height: 40px;
    border: 2px solid var(--primary);
    border-radius: 20px;
    padding: 0 45px 0 20px;
    font-size: 0.9rem;
    outline: none;
    transition: var(--transition);
}
.search-box input:focus { box-shadow: 0 0 0 3px rgba(255,107,0,0.15); }
.search-box button {
    position: absolute; right: 4px; top: 4px;
    width: 32px; height: 32px;
    background: var(--primary);
    border: none; border-radius: 50%;
    color: #fff; cursor: pointer;
    display: flex; align-items: center; justify-content: center;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 16px;
    flex-shrink: 0;
}

.app-download {
    display: flex; align-items: center; gap: 6px;
    color: var(--text-secondary); font-size: 0.85rem;
}
.app-download:hover { color: var(--primary); }

.header-link { color: var(--text-secondary); font-size: 0.9rem; }
.header-link:hover { color: var(--primary); }
.divider { color: var(--border-color); }

.user-menu { position: relative; }
.user-name {
    display: flex; align-items: center; gap: 6px;
    color: var(--text-primary); font-size: 0.9rem;
    cursor: pointer; padding: 6px 12px;
    border-radius: var(--radius-md);
}
.user-name:hover { background: var(--bg-body); }
.user-dropdown {
    position: absolute; top: 100%; right: 0;
    background: #fff; border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg); min-width: 160px;
    padding: 8px 0; opacity: 0; visibility: hidden;
    transform: translateY(-10px); transition: var(--transition);
}
.user-menu:hover .user-dropdown { opacity: 1; visibility: visible; transform: translateY(0); }
.user-dropdown a {
    display: flex; align-items: center; gap: 8px;
    padding: 10px 16px; font-size: 0.85rem;
    color: var(--text-secondary);
}
.user-dropdown a:hover { background: var(--bg-body); color: var(--primary); }

/* ===== 主导航 ===== */
.main-nav { background: #fff; position: relative; }
.nav-inner {
    display: flex; align-items: center;
    height: 48px; gap: 0;
}

.category-trigger {
    display: flex; align-items: center; gap: 8px;
    background: var(--primary); color: #fff;
    padding: 0 24px; height: 48px;
    font-size: 0.95rem; font-weight: 500;
    cursor: pointer; flex-shrink: 0;
}

.nav-links {
    display: flex; align-items: center;
    flex: 1; overflow-x: auto;
}
.nav-links li { flex-shrink: 0; }
.nav-links a {
    display: flex; align-items: center; gap: 4px;
    padding: 0 18px; height: 48px;
    font-size: 0.9rem; color: var(--text-secondary);
    white-space: nowrap;
    position: relative;
}
.nav-links a:hover, .nav-links a.active {
    color: var(--primary);
}
.nav-links a.active::after {
    content: ''; position: absolute; bottom: 0; left: 18px; right: 18px;
    height: 2px; background: var(--primary);
}
.nav-links a .fa-crown { color: #ffd700; }

/* ===== 二级菜单面板（W3Cschool风格） ===== */
.category-trigger {
    position: relative;
    transition: background 0.2s ease;
}
.category-trigger .trigger-caret {
    margin-left: auto;
    font-size: 0.75rem;
    opacity: 0.85;
    transition: transform 0.2s ease;
}
.category-trigger:hover, .category-trigger.open {
    background: var(--primary-dark);
}
.category-trigger:hover .trigger-caret,
.category-trigger.open .trigger-caret {
    transform: rotate(180deg);
}

.category-mega {
    display: none;
    position: absolute;
    top: 48px;
    left: 0;
    right: 0;
    background: #fff;
    border-top: 1px solid var(--border-light);
    box-shadow: var(--shadow-lg);
    z-index: 999;
    padding: 20px 24px 24px;
    flex-wrap: wrap;
    gap: 32px;
}
.category-trigger:hover ~ .category-mega,
.main-nav:hover .category-mega,
.category-mega:hover,
.category-mega.show {
    display: flex;
}
.mega-col {
    flex: 1;
    min-width: 180px;
}
.mega-title {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 12px;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--primary);
    display: inline-block;
}
.mega-list li a {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 8px 0;
    font-size: 0.85rem;
    color: var(--text-secondary);
    transition: var(--transition);
}
.mega-list li a:hover {
    color: var(--primary);
    padding-left: 6px;
}
.mega-list li a .fa-chevron-right {
    font-size: 0.7rem;
    color: var(--text-muted);
    margin-left: auto;
}
.mega-item-name { flex: 1; }
.mega-tag {
    font-size: 0.62rem;
    padding: 1px 6px;
    border-radius: 3px;
    font-weight: 600;
}
.mega-tag.hot {
    background: #ff4d4f;
    color: #fff;
}

/* ===== Hero区域（蓝色背景） ===== */
.hero-section {
    background: #eaf2fb;
    padding: 16px 0;
}

.hero-inner {
    display: flex;
    gap: 16px;
    align-items: flex-start;
}

/* 左侧分类栏 */
.sidebar-categories {
    width: 200px;
    flex-shrink: 0;
    background: var(--bg-card);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}

.category-list li a {
    display: flex;
    align-items: center;
    padding: 11px 16px;
    color: var(--text-secondary);
    font-size: 0.88rem;
    transition: var(--transition);
    border-bottom: 1px solid var(--border-light);
}
.category-list li:last-child a { border-bottom: none; }
.category-list li a:hover {
    background: #fff7f0;
    color: var(--primary);
}
.cat-name { flex: 1; }
.cat-tag {
    font-size: 0.65rem;
    padding: 1px 5px;
    border-radius: 3px;
    margin-right: 6px;
    font-weight: 600;
}
.cat-tag.hot {
    background: #ff4d4f;
    color: #fff;
}
.category-list li a .fa-chevron-right {
    font-size: 0.7rem;
    color: var(--text-muted);
}

/* 中间轮播区域 */
.banner-wrap {
    flex: 1;
    min-width: 0;
}

.banner-slider {
    position: relative;
    border-radius: var(--radius-md);
    overflow: hidden;
    background: #fff;
    box-shadow: var(--shadow-sm);
}

.banner-slides {
    position: relative;
    height: 280px;
}

.banner-slide {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.5s ease, visibility 0.5s ease;
}
.banner-slide.active {
    opacity: 1;
    visibility: visible;
}

.banner-bg {
    display: flex;
    align-items: center;
    padding: 0 40px;
    height: 100%;
    color: #fff;
}

.banner-text { flex: 1; }
.banner-text h2 {
    font-size: 1.8rem;
    margin-bottom: 10px;
    font-weight: 700;
}
.banner-text p {
    font-size: 1rem;
    opacity: 0.9;
    margin-bottom: 20px;
}
.btn-banner {
    display: inline-block;
    background: rgba(255,255,255,0.25);
    color: #fff;
    padding: 8px 24px;
    border-radius: 20px;
    font-size: 0.9rem;
    border: 1px solid rgba(255,255,255,0.4);
}
.btn-banner:hover {
    background: rgba(255,255,255,0.4);
}

.banner-decor {
    flex-shrink: 0;
    margin-left: 20px;
}

/* 轮播点 */
.banner-dots {
    position: absolute;
    bottom: 12px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 8px;
    z-index: 10;
}
.banner-dots .dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: rgba(255,255,255,0.5);
    cursor: pointer;
    transition: var(--transition);
}
.banner-dots .dot.active {
    background: #fff;
    width: 20px;
    border-radius: 4px;
}

/* 资讯滚动 */
.news-ticker {
    display: flex;
    align-items: center;
    gap: 12px;
    background: var(--bg-card);
    border-radius: var(--radius-md);
    padding: 10px 16px;
    margin-top: 12px;
    box-shadow: var(--shadow-sm);
}
.news-ticker > i { color: var(--primary); font-size: 0.9rem; }
.news-scroll {
    flex: 1;
    overflow: hidden;
    display: flex;
    gap: 32px;
}
.news-scroll a {
    font-size: 0.85rem;
    color: var(--text-secondary);
    white-space: nowrap;
}
.news-scroll a:hover { color: var(--primary); }
.news-date { color: var(--text-muted); margin-right: 8px; }
.news-more {
    color: var(--text-muted);
    font-size: 0.8rem;
    cursor: pointer;
}

/* 右侧登录面板 */
.quick-login-panel {
    width: 260px;
    flex-shrink: 0;
    background: var(--bg-card);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    padding: 20px;
}

.login-form-panel h4 {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.95rem;
    margin-bottom: 14px;
    color: var(--primary);
    font-weight: 600;
}
.login-form-panel .form-group {
    position: relative;
    margin-bottom: 10px;
}
.login-form-panel .form-group i:first-child {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    font-size: 0.85rem;
}
.login-form-panel input {
    width: 100%;
    height: 36px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 0 12px 0 34px;
    font-size: 0.82rem;
    outline: none;
    transition: var(--transition);
}
.login-form-panel input:focus { border-color: var(--primary); }
.login-form-panel .form-group input[type="password"] {
    padding-right: 32px;
}
.toggle-pwd {
    position: absolute;
    right: 8px;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    font-size: 0.8rem;
    line-height: 1;
    padding: 4px;
    z-index: 2;
}
.form-options {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.75rem;
    margin-bottom: 12px;
    color: var(--text-secondary);
}
.form-options label {
    display: flex;
    align-items: center;
    gap: 6px;
    cursor: pointer;
    color: var(--text-secondary);
    font-size: 0.75rem;
}
.form-options a { color: var(--text-muted); }
.form-options a:hover { color: var(--primary); }

/* 自定义复选框（W3Cschool风格） */
.form-options input[type="checkbox"],
.auth-options input[type="checkbox"] {
    appearance: none;
    -webkit-appearance: none;
    -moz-appearance: none;
    width: 16px;
    height: 16px;
    min-width: 16px;
    border: 1px solid var(--border-color);
    border-radius: 3px;
    background: var(--bg-card);
    cursor: pointer;
    position: relative;
    transition: var(--transition);
    vertical-align: middle;
}
.form-options input[type="checkbox"]:checked,
.auth-options input[type="checkbox"]:checked {
    background: var(--primary);
    border-color: var(--primary);
}
.form-options input[type="checkbox"]:checked::after,
.auth-options input[type="checkbox"]:checked::after {
    content: '';
    position: absolute;
    left: 4px;
    top: 1px;
    width: 5px;
    height: 9px;
    border: solid #fff;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}
.form-options input[type="checkbox"]:hover,
.auth-options input[type="checkbox"]:hover {
    border-color: var(--primary);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 8px 20px;
    border-radius: var(--radius-sm);
    font-size: 0.88rem;
    font-weight: 500;
    cursor: pointer;
    border: none;
    transition: var(--transition);
}
.btn-primary {
    background: var(--primary);
    color: #fff;
}
.btn-primary:hover { background: var(--primary-dark); }
.btn-block { width: 100%; }

.social-login {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    margin-top: 14px;
    padding-top: 14px;
    border-top: 1px solid var(--border-light);
}
.social-login a {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 0.9rem;
    transition: var(--transition);
}
.social-login a:hover { transform: scale(1.1); }
.social-login .wechat { background: #07c160; }
.social-login .qq { background: #12b7f5; }
.social-login .github { background: #333; }
.social-login a:last-child { background: var(--primary); font-size: 0.8rem; }

/* 用户信息面板 */
.user-info-panel { text-align: center; }
.user-avatar {
    width: 56px;
    height: 56px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 1.3rem;
    font-weight: 600;
    margin: 0 auto 10px;
}
.user-welcome { font-size: 0.85rem; color: var(--text-secondary); margin-bottom: 14px; }
.user-stats {
    display: flex;
    justify-content: center;
    gap: 16px;
    margin-bottom: 16px;
}
.stat-item { text-align: center; }
.stat-num {
    display: block;
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--primary);
}
.stat-label { font-size: 0.7rem; color: var(--text-muted); }

/* ===== 主体内容 ===== */
.main-wrapper {
    padding: 20px 0;
}

.content-inner { }

/* 课程列表页两栏布局（侧边栏 + 内容） */
.courses-layout {
    display: flex;
    gap: 20px;
    align-items: flex-start;
    max-width: 1200px;
    margin: 0 auto;
    padding: 24px 16px;
}
.courses-layout > .sidebar-categories {
    width: 220px;
    flex-shrink: 0;
    background: var(--bg-card);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
    position: sticky;
    top: 12px;
}
.courses-layout > .sidebar-categories .category-menu,
.courses-layout > .sidebar-categories .sidebar-section {
    padding: 16px;
}
.courses-layout > .sidebar-categories .category-menu h3,
.courses-layout > .sidebar-categories .sidebar-section h3 {
    font-size: 0.9rem;
    margin-bottom: 12px;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 6px;
}
.courses-layout > .sidebar-categories .category-list li a {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 9px 12px;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    font-size: 0.85rem;
    transition: var(--transition);
}
.courses-layout > .sidebar-categories .category-list li a:hover {
    background: #fff7f0;
    color: var(--primary);
}
.courses-layout > .sidebar-categories .category-list li a.active {
    background: rgba(242, 126, 23, 0.1);
    color: var(--primary);
    font-weight: 500;
}
.courses-layout > .sidebar-categories .cat-icon {
    width: 22px;
    text-align: center;
}
.courses-layout > .sidebar-categories .sidebar-section {
    border-top: 1px solid var(--border-light);
}
.courses-layout > .main-content {
    flex: 1;
    min-width: 0;
}

/* 实战训练 + 学习路径 并排 */
.dual-section {
    display: flex;
    gap: 20px;
    margin-bottom: 20px;
}

.practice-section {
    width: 280px;
    flex-shrink: 0;
}

.path-section {
    flex: 1;
    min-width: 0;
}

.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
    flex-wrap: wrap;
    gap: 12px;
}
.section-header h2 {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1rem;
    font-weight: 600;
}
.section-header h2 i { color: var(--primary); font-size: 0.9rem; }
.section-subtitle {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.more-link {
    display: flex;
    align-items: center;
    gap: 4px;
    font-size: 0.8rem;
    color: var(--text-muted);
}
.more-link:hover { color: var(--primary); }

/* 实战训练列表 */
.practice-list {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}
.practice-main {
    display: block;
    padding: 16px;
    border-bottom: 1px solid var(--border-light);
}
.practice-img {
    border-radius: var(--radius-md);
    padding: 20px;
    color: #fff;
    text-align: center;
    min-height: 140px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}
.practice-img span {
    font-size: 0.8rem;
    opacity: 0.9;
    margin-bottom: 4px;
}
.practice-img h3 {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 4px;
}
.practice-img p {
    font-size: 0.8rem;
    opacity: 0.85;
}

.practice-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    border-bottom: 1px solid var(--border-light);
    transition: var(--transition);
}
.practice-item:last-child { border-bottom: none; }
.practice-item:hover { background: #fafafa; }
.practice-icon-box {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}
.practice-emoji { font-size: 1.2rem; }
.practice-info { flex: 1; min-width: 0; }
.practice-info h4 {
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 4px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}
.practice-meta {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.72rem;
    color: var(--text-muted);
}
.difficulty-tag {
    background: #e6f7ff;
    color: var(--secondary);
    padding: 1px 6px;
    border-radius: 3px;
    font-size: 0.65rem;
}

/* 学习路径 */
.path-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
}

.path-card {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 1px solid var(--border-light);
}
.path-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}
.path-banner {
    height: 90px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}
.path-icon { font-size: 2rem; }
.path-tag {
    position: absolute;
    top: 6px;
    right: 6px;
    background: rgba(255,255,255,0.9);
    padding: 1px 6px;
    border-radius: 3px;
    font-size: 0.65rem;
    color: var(--text-secondary);
}
.path-body { padding: 10px 12px; }
.path-body h3 {
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 4px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}
.path-body p { font-size: 0.75rem; color: var(--text-muted); }

/* 课程区块 */
.content-section {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    padding: 20px;
    margin-bottom: 20px;
}

.section-tabs {
    display: flex;
    gap: 4px;
}
.section-tabs a {
    padding: 5px 14px;
    border-radius: var(--radius-sm);
    font-size: 0.82rem;
    color: var(--text-secondary);
}
.section-tabs a:hover, .section-tabs a.active {
    background: #fff7f0;
    color: var(--primary);
}

/* 课程卡片网格 */
.course-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 16px;
}

.course-card {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 1px solid var(--border-light);
}
.course-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.card-banner {
    height: 110px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}
.card-icon { font-size: 2.5rem; }
.card-badge {
    position: absolute;
    top: 6px;
    right: 6px;
    background: rgba(255,255,255,0.9);
    padding: 2px 8px;
    border-radius: 10px;
    font-size: 0.7rem;
    color: var(--text-secondary);
}

.card-body { padding: 12px; }
.card-title {
    font-size: 0.88rem;
    font-weight: 600;
    margin-bottom: 5px;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
}
.card-desc {
    font-size: 0.78rem;
    color: var(--text-muted);
    margin-bottom: 8px;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
}
.card-meta {
    display: flex;
    gap: 10px;
    font-size: 0.72rem;
    color: var(--text-muted);
}
.card-meta i { margin-right: 2px; }

.card-progress {
    margin-top: 8px;
}
.progress-bar {
    height: 4px;
    background: var(--border-light);
    border-radius: 2px;
    overflow: hidden;
}
.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary) 0%, var(--primary-dark) 100%);
    border-radius: 2px;
    transition: width 0.5s ease;
}
.progress-text {
    font-size: 0.72rem;
    color: var(--primary);
    margin-top: 3px;
}

/* 极客教程 */
.geek-section .section-header { margin-bottom: 16px; }
.geek-grid {
    display: grid;
    grid-template-columns: repeat(8, 1fr);
    gap: 12px;
}
.geek-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    padding: 12px;
    border-radius: var(--radius-md);
    transition: var(--transition);
    text-align: center;
}
.geek-card:hover {
    background: #fafafa;
}
.geek-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 0.78rem;
    font-weight: 700;
}
.geek-card span {
    font-size: 0.78rem;
    color: var(--text-secondary);
}

/* ===== 底部 ===== */
.site-footer {
    background: #2c3e50;
    color: #bdc3c7;
    padding: 40px 0 20px;
    margin-top: 20px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 28px;
}

.footer-brand .logo { margin-bottom: 12px; }
.footer-brand .logo-name { color: #fff; }
.footer-brand p { font-size: 0.82rem; line-height: 1.8; }

.footer-links h4 {
    color: #fff;
    font-size: 0.9rem;
    margin-bottom: 14px;
}
.footer-links li { margin-bottom: 8px; }
.footer-links a {
    font-size: 0.82rem;
    color: #bdc3c7;
}
.footer-links a:hover { color: var(--primary); }

.footer-bottom {
    border-top: 1px solid #34495e;
    padding-top: 20px;
    text-align: center;
    font-size: 0.78rem;
}

/* ===== 悬浮工具 ===== */
.float-tools {
    position: fixed;
    right: 16px;
    bottom: 80px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    z-index: 999;
}
.float-btn {
    width: 40px;
    height: 40px;
    background: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-md);
    color: var(--text-secondary);
    font-size: 1rem;
    transition: var(--transition);
}
.float-btn:hover {
    background: var(--primary);
    color: #fff;
    transform: scale(1.1);
}

/* ===== 响应式 ===== */
@media (max-width: 1200px) {
    .sidebar-categories { display: none; }
    .quick-login-panel { display: none; }
    .banner-slides { height: 220px; }
    .banner-bg { padding: 0 24px; }
    .banner-text h2 { font-size: 1.4rem; }
    .banner-decor { display: none; }
    .path-grid { grid-template-columns: repeat(2, 1fr); }
    .geek-grid { grid-template-columns: repeat(4, 1fr); }
    .category-mega { gap: 20px; }
    .mega-col { min-width: 140px; }
}

@media (max-width: 992px) {
    .dual-section { flex-direction: column; }
    .practice-section { width: 100%; }
    .path-grid { grid-template-columns: repeat(2, 1fr); }
    .course-grid { grid-template-columns: repeat(3, 1fr); }
    .geek-grid { grid-template-columns: repeat(4, 1fr); }
    .category-mega { position: fixed; top: auto; left: 0; right: 0; max-height: 70vh; overflow-y: auto; }
    .category-trigger { padding: 0 16px; }
    .courses-layout { flex-direction: column; }
    .courses-layout > .sidebar-categories {
        width: 100%;
        position: static;
        display: grid;
        grid-template-columns: 1fr;
    }
    .courses-layout > .sidebar-categories .category-menu .category-list {
        display: flex;
        flex-wrap: wrap;
        gap: 6px;
    }
    .courses-layout > .sidebar-categories .category-list li a {
        border-radius: 20px;
        border: 1px solid var(--border-light);
        padding: 6px 14px;
    }
}

@media (max-width: 768px) {
    .header-inner { flex-wrap: wrap; height: auto; padding: 10px 0; }
    .search-box { order: 3; max-width: 100%; width: 100%; margin-top: 8px; }
    .nav-links a { padding: 0 12px; font-size: 0.8rem; }
    .banner-slides { height: 180px; }
    .course-grid { grid-template-columns: repeat(2, 1fr); }
    .path-grid { grid-template-columns: repeat(2, 1fr); }
    .geek-grid { grid-template-columns: repeat(4, 1fr); }
    .footer-grid { grid-template-columns: 1fr 1fr; }
    .category-mega { flex-direction: column; gap: 16px; padding: 16px 20px 20px; }
    .mega-col { min-width: 100%; }
    .nav-inner { height: 44px; }
    .category-trigger { height: 44px; padding: 0 14px; font-size: 0.85rem; }
    .category-mega { top: 44px; }
    .banner-wrap { margin-top: 0; }
}

@media (max-width: 480px) {
    .course-grid { grid-template-columns: 1fr; }
    .path-grid { grid-template-columns: 1fr; }
    .geek-grid { grid-template-columns: repeat(2, 1fr); }
    .section-header { flex-direction: column; align-items: flex-start; }
    .footer-grid { grid-template-columns: 1fr; }
    .banner-text h2 { font-size: 1.2rem; }
    .banner-text p { font-size: 0.85rem; margin-bottom: 14px; }
    .banner-bg { padding: 0 20px; }
    .btn-banner { padding: 7px 18px; font-size: 0.82rem; }
    .news-ticker { padding: 8px 12px; }
    .header-actions .app-download { display: none; }
}

/* ===== 课程详情页 ===== */
.course-detail-banner {
    background: linear-gradient(135deg, #1a365d 0%, #2d5a87 100%);
    color: #fff;
    padding: 40px 0;
}
.course-detail-banner .container {
    display: flex;
    align-items: center;
    gap: 32px;
}
.course-detail-icon { font-size: 5rem; }
.course-detail-info h1 { font-size: 2rem; margin-bottom: 12px; }
.course-detail-info p { opacity: 0.9; margin-bottom: 16px; }
.course-detail-meta {
    display: flex;
    gap: 20px;
    font-size: 0.9rem;
}

.course-layout {
    display: flex;
    gap: 24px;
    max-width: 1400px;
    margin: 0 auto;
    padding: 24px 20px;
}

.course-sidebar {
    width: 300px;
    flex-shrink: 0;
}

.course-nav-card {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    padding: 20px;
    position: sticky;
    top: 120px;
}
.course-nav-card h3 {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1rem;
    margin-bottom: 16px;
}
.chapter-list { display: flex; flex-direction: column; gap: 4px; }
.chapter-list a {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 12px;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    color: var(--text-secondary);
    transition: var(--transition);
}
.chapter-list a:hover, .chapter-list a.active {
    background: #fff7f0;
    color: var(--primary);
}
.chapter-list a .ch-num {
    width: 28px;
    height: 28px;
    background: var(--border-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: 600;
    flex-shrink: 0;
}
.chapter-list a:hover .ch-num, .chapter-list a.active .ch-num {
    background: var(--primary);
    color: #fff;
}
.chapter-list a .ch-status {
    margin-left: auto;
    font-size: 0.8rem;
}

.lesson-main {
    flex: 1;
    min-width: 0;
    background: var(--bg-card);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    padding: 32px;
}

.lesson-header {
    margin-bottom: 24px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border-light);
}
.lesson-header h1 { font-size: 1.6rem; margin-bottom: 8px; }
.lesson-header .lesson-meta {
    display: flex;
    gap: 16px;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.lesson-body {
    font-size: 1rem;
    line-height: 1.8;
    color: var(--text-primary);
}
.lesson-body h2 {
    font-size: 1.3rem;
    margin: 28px 0 14px;
    color: var(--text-primary);
}
.lesson-body h3 {
    font-size: 1.1rem;
    margin: 20px 0 10px;
    color: var(--text-secondary);
}
.lesson-body p { margin-bottom: 14px; }
.lesson-body ul, .lesson-body ol {
    margin: 12px 0 12px 24px;
    padding-left: 16px;
}
.lesson-body ul { list-style: disc; }
.lesson-body ol { list-style: decimal; }
.lesson-body li { margin-bottom: 6px; }
.lesson-body blockquote {
    border-left: 4px solid var(--primary);
    background: #fff7f0;
    padding: 12px 16px;
    margin: 16px 0;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.lesson-body code {
    background: #f5f5f5;
    padding: 2px 6px;
    border-radius: 3px;
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 0.9em;
    color: #e83e8c;
}
.lesson-body hr {
    border: none;
    border-top: 1px solid var(--border-light);
    margin: 24px 0;
}

/* 代码块 */
.code-wrapper {
    margin: 20px 0;
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}
.code-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: #2d2d2d;
    padding: 10px 16px;
    color: #fff;
    border-radius: var(--radius-md) var(--radius-md) 0 0;
}
.code-lang {
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}
.code-actions { display: flex; gap: 8px; }
.copy-code-btn {
    background: rgba(255,255,255,0.1);
    border: none;
    color: #fff;
    padding: 4px 12px;
    border-radius: 4px;
    font-size: 0.75rem;
    cursor: pointer;
    transition: var(--transition);
}
.copy-code-btn:hover { background: rgba(255,255,255,0.2); }
.code-table-wrap {
    background: #1e1e1e;
    overflow-x: auto;
    max-width: 100%;
}
.code-table {
    width: 100%;
    border-collapse: collapse;
    font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
    font-size: 0.9rem;
}
.code-table td {
    padding: 6px 12px;
    white-space: pre;
    color: #d4d4d4;
}
.line-no {
    width: 40px;
    text-align: right;
    color: #858585;
    background: #1e1e1e;
    border-right: 1px solid #333;
    user-select: none;
    position: sticky;
    left: 0;
}
.line-content { color: #d4d4d4; }

/* 课程操作栏 */
.lesson-actions {
    display: flex;
    gap: 12px;
    margin-top: 32px;
    padding-top: 24px;
    border-top: 1px solid var(--border-light);
}
.lesson-actions .btn {
    padding: 10px 20px;
    font-size: 0.9rem;
}
.lesson-actions .btn-favorite { background: #fff0f0; color: var(--danger); }
.lesson-actions .btn-favorite:hover { background: var(--danger); color: #fff; }
.lesson-actions .btn-favorite.active { background: var(--danger); color: #fff; }

/* 笔记区域 */
.note-section {
    margin-top: 32px;
    padding: 24px;
    background: #fafafa;
    border-radius: var(--radius-md);
}
.note-section h3 {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 16px;
}
.note-section textarea {
    width: 100%;
    min-height: 120px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 12px;
    font-size: 0.9rem;
    resize: vertical;
    outline: none;
}
.note-section textarea:focus { border-color: var(--primary); }

/* 分页导航 */
.lesson-nav {
    display: flex;
    justify-content: space-between;
    margin-top: 32px;
    padding-top: 24px;
    border-top: 1px solid var(--border-light);
}
.lesson-nav a {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    background: var(--bg-body);
    border-radius: var(--radius-md);
    font-size: 0.9rem;
    color: var(--text-secondary);
}
.lesson-nav a:hover { background: #fff7f0; color: var(--primary); }

/* ===== 登录注册页 ===== */
.auth-page {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 40px 20px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    overflow: hidden;
}
/* 背景装饰圆 */
.auth-page::before {
    content: '';
    position: absolute;
    top: -120px;
    right: -120px;
    width: 380px;
    height: 380px;
    border-radius: 50%;
    background: rgba(255,255,255,0.08);
}
.auth-page::after {
    content: '';
    position: absolute;
    bottom: -160px;
    left: -160px;
    width: 420px;
    height: 420px;
    border-radius: 50%;
    background: rgba(255,255,255,0.06);
}

.auth-card {
    position: relative;
    z-index: 1;
    background: #fff;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.18);
    width: 100%;
    max-width: 440px;
    padding: 40px 44px;
    overflow: hidden;
}
/* 顶部品牌色条 */
.auth-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 5px;
    background: linear-gradient(90deg, #ff6b00, #ff9a3c, #ff6b00);
}

.auth-logo {
    text-align: center;
    margin-bottom: 28px;
}
.auth-logo .logo-icon {
    width: 68px;
    height: 68px;
    margin: 0 auto 14px;
    font-size: 2.2rem;
    border-radius: 18px;
    background: linear-gradient(135deg, #ff6b00, #ff9a3c);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 8px 20px rgba(255,107,0,0.25);
}
.auth-logo .logo-name {
    font-size: 1.6rem;
    background: linear-gradient(135deg, #ff6b00, #ff9a3c);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}
.auth-logo .logo-slogan { color: var(--text-muted); font-size: 0.9rem; }

.auth-tabs {
    display: flex;
    margin-bottom: 28px;
    background: #f5f7fa;
    border-radius: 10px;
    padding: 4px;
    gap: 4px;
}
.auth-tabs a {
    flex: 1;
    text-align: center;
    padding: 10px;
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-secondary);
    border-radius: 8px;
    transition: var(--transition);
}
.auth-tabs a.active {
    color: var(--primary);
    background: #fff;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}

.auth-form .form-group {
    position: relative;
    margin-bottom: 16px;
}
.auth-form .form-group i:first-child {
    position: absolute;
    left: 16px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    font-size: 0.95rem;
    transition: color 0.2s;
    z-index: 2;
}
.auth-form .form-group:focus-within i:first-child { color: var(--primary); }
.auth-form input {
    width: 100%;
    height: 46px;
    border: 1.5px solid var(--border-color);
    border-radius: 10px;
    padding: 0 16px 0 44px;
    font-size: 0.92rem;
    outline: none;
    background: #fafbfc;
    transition: all 0.2s;
    color: var(--text-primary);
}
.auth-form input:focus {
    border-color: var(--primary);
    background: #fff;
    box-shadow: 0 0 0 4px rgba(255,107,0,0.08);
}
.auth-form .form-group input[type="password"] {
    padding-right: 44px;
}
.auth-form .toggle-pwd {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    line-height: 1;
    padding: 6px;
    z-index: 2;
}
.auth-form .toggle-pwd:hover { color: var(--primary); }

.auth-options {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.85rem;
    margin-bottom: 20px;
}
.auth-options label {
    display: flex;
    align-items: center;
    gap: 6px;
    cursor: pointer;
    color: var(--text-secondary);
}
.auth-options a { color: var(--primary); font-weight: 500; }
.auth-options a:hover { text-decoration: underline; }

.auth-form .btn-block {
    height: 48px;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    background: linear-gradient(135deg, #ff6b00, #ff9a3c);
    box-shadow: 0 6px 16px rgba(255,107,0,0.3);
    border: none;
    color: #fff;
    cursor: pointer;
    transition: all 0.2s;
}
.auth-form .btn-block:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 22px rgba(255,107,0,0.35);
}
.auth-form .btn-block:active { transform: translateY(0); }

.auth-divider {
    display: flex;
    align-items: center;
    gap: 12px;
    margin: 24px 0;
    color: var(--text-muted);
    font-size: 0.8rem;
}
.auth-divider::before, .auth-divider::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--border-light);
}

.social-login-row {
    display: flex;
    justify-content: center;
    gap: 16px;
}
.social-login-row a {
    width: 42px;
    height: 42px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 1.15rem;
    transition: all 0.2s;
    box-shadow: 0 2px 6px rgba(0,0,0,0.1);
}
.social-login-row a:hover {
    transform: scale(1.12);
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}
.social-login-row .wechat { background: #07c160; }
.social-login-row .qq { background: #12b7f5; }
.social-login-row .github { background: #333; }
.social-login-row .weibo { background: #e6162d; }

.auth-footer {
    text-align: center;
    margin-top: 22px;
    font-size: 0.78rem;
    color: var(--text-muted);
}
.auth-footer a { color: var(--primary); }

/* 找回密码头部 */
.auth-forgot-title {
    text-align: center;
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 6px;
}
.auth-forgot-sub {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-bottom: 26px;
}

/* 移动端适配 */
@media (max-width: 480px) {
    .auth-card { padding: 32px 24px; }
    .auth-logo .logo-icon { width: 56px; height: 56px; font-size: 1.8rem; }
}

/* 密码强度条 */
.pwd-strength {
    height: 4px;
    background: #e5e5e5;
    border-radius: 2px;
    margin-top: 8px;
    overflow: hidden;
    position: relative;
}
.pwd-bar {
    display: block;
    height: 100%;
    width: 0;
    border-radius: 2px;
    background: #e5e5e5;
    transition: all 0.3s;
}
.pwd-strength[data-level]::after {
    content: attr(data-level);
    position: absolute;
    right: 0;
    top: -14px;
    font-size: 0.7rem;
    color: var(--text-muted);
}

/* 轮播左右箭头 */
.banner-prev, .banner-next {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: rgba(255,255,255,0.85);
    border: none;
    color: #333;
    font-size: 0.9rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    opacity: 0;
    transition: all 0.25s;
    z-index: 5;
}
.banner-prev { left: 14px; }
.banner-next { right: 14px; }
.banner-slider:hover .banner-prev,
.banner-slider:hover .banner-next {
    opacity: 1;
}
.banner-prev:hover, .banner-next:hover {
    background: var(--primary);
    color: #fff;
    transform: translateY(-50%) scale(1.08);
}

/* 平台特色 */
.feature-section {
    background: #fff;
    border-radius: var(--radius-md);
    padding: 28px;
    box-shadow: var(--shadow-sm);
    margin-bottom: 24px;
}
.feature-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}
.feature-card {
    text-align: center;
    padding: 24px 16px;
    border-radius: var(--radius-md);
    background: linear-gradient(180deg, #fafbfc 0%, #fff 100%);
    border: 1px solid var(--border-light);
    transition: var(--transition);
}
.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary);
}
.feature-ico {
    width: 60px;
    height: 60px;
    margin: 0 auto 14px;
    border-radius: 16px;
    background: linear-gradient(135deg, var(--primary), #ff9a3c);
    color: #fff;
    font-size: 1.6rem;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 6px 16px rgba(255,107,0,0.25);
}
.feature-card h3 {
    font-size: 1.05rem;
    color: var(--text-primary);
    margin-bottom: 8px;
}
.feature-card p {
    font-size: 0.85rem;
    color: var(--text-muted);
    line-height: 1.6;
    margin: 0;
}

@media (max-width: 992px) {
    .feature-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 480px) {
    .feature-grid { grid-template-columns: 1fr; }
}

/* ===== 后台管理 ===== */
.admin-layout {
    display: flex;
    min-height: 100vh;
}

.admin-sidebar {
    width: 240px;
    flex-shrink: 0;
    background: #1a1a2e;
    color: #a0a0b0;
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    overflow-y: auto;
}

.admin-sidebar .logo {
    padding: 20px;
    border-bottom: 1px solid #2a2a3e;
}
.admin-sidebar .logo-name { color: #fff; }

.admin-nav { padding: 16px 0; }
.admin-nav li a {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px 20px;
    font-size: 0.9rem;
    transition: var(--transition);
}
.admin-nav li a:hover, .admin-nav li a.active {
    background: rgba(255,107,0,0.1);
    color: var(--primary);
}
.admin-nav li a i { width: 20px; text-align: center; }

.admin-main {
    flex: 1;
    margin-left: 240px;
    background: var(--bg-body);
    min-height: 100vh;
}

.admin-header {
    background: #fff;
    padding: 16px 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 100;
}

.admin-content { padding: 24px; }

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 20px;
    margin-bottom: 24px;
}

.stat-card {
    background: #fff;
    border-radius: var(--radius-md);
    padding: 24px;
    box-shadow: var(--shadow-sm);
    display: flex;
    align-items: center;
    gap: 16px;
}
.stat-card-icon {
    width: 56px;
    height: 56px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
}
.stat-card-info h4 { font-size: 1.8rem; font-weight: 700; }
.stat-card-info p { font-size: 0.85rem; color: var(--text-muted); }

.data-table {
    width: 100%;
    background: #fff;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}
.data-table table { width: 100%; border-collapse: collapse; }
.data-table th, .data-table td {
    padding: 14px 16px;
    text-align: left;
    font-size: 0.9rem;
}
.data-table th {
    background: #fafafa;
    font-weight: 600;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-light);
}
.data-table td { border-bottom: 1px solid var(--border-light); }
.data-table tr:hover td { background: #fafafa; }

.table-actions { display: flex; gap: 8px; }
.table-actions .btn {
    padding: 6px 12px;
    font-size: 0.8rem;
}
.btn-sm { padding: 6px 14px; font-size: 0.8rem; }
.btn-edit { background: #e6f7ff; color: var(--secondary); }
.btn-delete { background: #fff1f0; color: var(--danger); }

/* 表单 */
.form-card {
    background: #fff;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    padding: 32px;
    max-width: 800px;
}
.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}
.form-label {
    display: block;
    margin-bottom: 6px;
    font-size: 0.9rem;
    font-weight: 500;
}
.form-input, .form-select, .form-textarea {
    width: 100%;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 10px 14px;
    font-size: 0.9rem;
    outline: none;
    transition: var(--transition);
}
.form-input:focus, .form-select:focus, .form-textarea:focus {
    border-color: var(--primary);
}
.form-textarea { min-height: 120px; resize: vertical; }

/* 标签页 */
.tab-nav {
    display: flex;
    gap: 4px;
    margin-bottom: 20px;
    border-bottom: 2px solid var(--border-light);
}
.tab-nav a {
    padding: 12px 20px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    position: relative;
}
.tab-nav a.active {
    color: var(--primary);
}
.tab-nav a.active::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary);
}

/* 搜索页 */
.search-results {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    padding: 24px;
}
.search-item {
    padding: 20px 0;
    border-bottom: 1px solid var(--border-light);
}
.search-item:last-child { border: none; }
.search-item h3 { font-size: 1.1rem; margin-bottom: 8px; }
.search-item h3 a { color: var(--secondary); }
.search-item h3 a:hover { color: var(--primary); }
.search-item p { color: var(--text-secondary); font-size: 0.9rem; }
.search-item .search-meta {
    display: flex;
    gap: 16px;
    margin-top: 8px;
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* 消息提示 */
.alert {
    padding: 12px 16px;
    border-radius: var(--radius-sm);
    margin-bottom: 16px;
    font-size: 0.9rem;
}
.alert-success { background: #f6ffed; color: #52c41a; border: 1px solid #b7eb8f; }
.alert-error { background: #fff1f0; color: #f5222d; border: 1px solid #ffa39e; }
.alert-warning { background: #fffbe6; color: #faad14; border: 1px solid #ffe58f; }

/* 分页 */
.pagination {
    display: flex;
    justify-content: center;
    gap: 4px;
    margin-top: 24px;
}
.pagination a, .pagination span {
    padding: 8px 14px;
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
}
.pagination a {
    background: #fff;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}
.pagination a:hover { border-color: var(--primary); color: var(--primary); }
.pagination .current {
    background: var(--primary);
    color: #fff;
}

/* 练习场 */
.playground-layout {
    display: flex;
    flex-direction: column;
    height: calc(100vh - 112px);
}
.playground-toolbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 20px;
    background: #fff;
    border-bottom: 1px solid var(--border-light);
}
.playground-editor {
    display: flex;
    flex: 1;
    overflow: hidden;
}
.editor-pane, .output-pane {
    flex: 1;
    display: flex;
    flex-direction: column;
}
.editor-pane { border-right: 1px solid var(--border-light); }
.pane-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 8px 16px;
    background: #fafafa;
    border-bottom: 1px solid var(--border-light);
    font-size: 0.85rem;
    font-weight: 500;
}
.pane-body {
    flex: 1;
    overflow: auto;
}
.pane-body textarea {
    width: 100%;
    height: 100%;
    border: none;
    padding: 16px;
    font-family: 'Consolas', monospace;
    font-size: 0.9rem;
    resize: none;
    outline: none;
}
.output-content {
    padding: 16px;
    font-family: 'Consolas', monospace;
    font-size: 0.85rem;
    white-space: pre-wrap;
}

/* 旧版兼容 */
.page-header { display: none; }
.container-old { max-width: 1400px; margin: 0 auto; padding: 0 20px; }

/* ============================================
   新风格页面公共样式（topbar/header/nav/page-banner/layout/footer）
   适用于：practices/paths/tutorials/tools/downloads/vip/ai-ide/questions/favorites/notes/path/practice
   ============================================ */

/* 顶部信息栏 */
.topbar {
    background: #f8f5f2;
    border-bottom: 1px solid var(--border-light);
    font-size: 0.78rem;
    color: var(--text-secondary);
}
.topbar-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 6px 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
}
.topbar-right {
    display: flex;
    align-items: center;
    gap: 10px;
}
.topbar-right a {
    color: var(--text-secondary);
    transition: var(--transition);
}
.topbar-right a:hover { color: var(--primary); }
.topbar .sep { color: var(--text-muted); }

/* 页面头部（logo + 搜索） */
.header {
    background: #fff;
    border-bottom: 1px solid var(--border-light);
}
.header .header-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 14px 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}
.header .logo {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-shrink: 0;
}
.header .logo-icon {
    width: 42px;
    height: 42px;
    background: var(--gradient-1);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 22px;
}
.header .logo-text {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    white-space: nowrap;
}
.header-search {
    flex: 1;
    max-width: 420px;
    margin-left: auto;
}
.header-search form {
    display: flex;
    align-items: center;
    border: 1.5px solid var(--border-color);
    border-radius: 24px;
    overflow: hidden;
    background: var(--bg-primary);
    transition: var(--transition);
}
.header-search form:focus-within {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(242, 126, 23, 0.12);
}
.header-search .search-input {
    flex: 1;
    border: none;
    outline: none;
    background: transparent;
    padding: 9px 16px;
    font-size: 0.88rem;
    color: var(--text-primary);
}
.header-search .search-btn {
    background: var(--primary);
    border: none;
    color: #fff;
    width: 40px;
    height: 38px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: var(--transition);
}
.header-search .search-btn:hover { background: var(--primary-dark); }

/* 主导航（新风格 .nav-list） */
.header + .main-nav,
body > .main-nav {
    background: #fff;
    border-bottom: 1px solid var(--border-light);
    box-shadow: 0 1px 4px rgba(0,0,0,0.04);
}
.main-nav .nav-list {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 16px;
    display: flex;
    align-items: center;
    gap: 4px;
    overflow-x: auto;
    list-style: none;
}
.main-nav .nav-list li { flex-shrink: 0; }
.main-nav .nav-list a {
    display: flex;
    align-items: center;
    gap: 5px;
    padding: 12px 14px;
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 500;
    border-radius: var(--radius-sm);
    white-space: nowrap;
    transition: var(--transition);
    position: relative;
}
.main-nav .nav-list a:hover {
    color: var(--primary);
    background: #fff7f0;
}
.main-nav .nav-list a.active {
    color: var(--primary);
    font-weight: 600;
}
.main-nav .nav-list a.active::after {
    content: '';
    position: absolute;
    left: 14px;
    right: 14px;
    bottom: 0;
    height: 2px;
    background: var(--primary);
    border-radius: 2px;
}
.main-nav .nav-list a.nav-highlight {
    color: #fff;
    background: linear-gradient(135deg, var(--primary), #ff9a3c);
    border-radius: 16px;
    padding: 7px 16px;
    font-weight: 600;
}
.main-nav .nav-list a.nav-highlight:hover {
    background: linear-gradient(135deg, var(--primary-dark), var(--primary));
    color: #fff;
}

/* 页面横幅 */
.page-banner {
    color: #fff;
    padding: 44px 0;
}
.page-banner-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}
.page-banner h1 {
    font-size: 1.9rem;
    font-weight: 700;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 12px;
}
.page-banner p {
    opacity: 0.92;
    font-size: 1rem;
    margin: 0;
}

/* 内容布局 */
.layout {
    max-width: 1200px;
    margin: 0 auto;
    padding: 28px 16px 40px;
}
.layout-main-wide { width: 100%; }
.layout-main, .layout-sidebar { }

/* 通用卡片 */
.layout .card {
    background: #fff;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    padding: 20px;
}

/* 区块标题 */
.layout .section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 20px;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
}

/* 筛选标签 */
.layout .filter-tags {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}
.layout .filter-tags .tag {
    padding: 5px 16px;
    border-radius: 16px;
    background: #f0f2f5;
    font-size: 0.82rem;
    color: var(--text-secondary);
    transition: var(--transition);
}
.layout .filter-tags .tag:hover {
    background: #fff7f0;
    color: var(--primary);
}
.layout .filter-tags .tag.active {
    background: var(--primary);
    color: #fff;
}

/* 新风格页脚 */
.footer {
    background: #2c3e50;
    color: #bdc3c7;
    margin-top: 20px;
}
.footer-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 28px 20px 18px;
}
.footer-section h4 {
    color: #fff;
    font-size: 0.9rem;
    margin-bottom: 10px;
}
.footer-section p {
    font-size: 0.82rem;
    line-height: 1.8;
}
.footer-bottom {
    border-top: 1px solid #3d5266;
    margin-top: 20px;
    padding-top: 16px;
    text-align: center;
    font-size: 0.78rem;
}
.footer-bottom a { color: #bdc3c7; }
.footer-bottom a:hover { color: var(--primary); }

/* 通用工具卡片 */
.tool-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 16px;
}
.tool-card {
    background: #fff;
    border-radius: var(--radius-md);
    padding: 26px 16px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    text-decoration: none;
    color: inherit;
    display: block;
    border: 1px solid transparent;
}
.tool-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary);
}
.tool-card .icon { font-size: 2.6rem; margin-bottom: 10px; display: block; }
.tool-card h4 { margin: 0 0 6px; font-size: 1rem; color: var(--text-primary); }
.tool-card p { color: var(--text-muted); font-size: 0.8rem; margin: 0; }

/* 教程卡片 */
.tutorial-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 16px;
}
.tutorial-item {
    background: #fff;
    border-radius: var(--radius-md);
    padding: 22px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    text-decoration: none;
    color: inherit;
    border-left: 4px solid var(--primary);
}
.tutorial-item:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}
.tutorial-item h4 { color: var(--text-primary); font-size: 1.05rem; }
.tutorial-item p { color: var(--text-secondary); font-size: 0.9rem; }

/* 资料下载卡片 */
.dl-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 16px;
}
.dl-card {
    background: #fff;
    border-radius: var(--radius-md);
    padding: 20px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    display: flex;
    gap: 16px;
    align-items: flex-start;
}
.dl-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}
.dl-card .dl-icon { font-size: 2.5rem; flex-shrink: 0; }
.dl-card h4 { color: var(--text-primary); margin: 0 0 4px; }
.dl-card p { color: var(--text-secondary); font-size: 0.85rem; margin: 0 0 6px; }
.dl-card .dl-meta {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 10px;
}
.dl-card .dl-type {
    font-size: 0.75rem;
    background: #f0f2f5;
    padding: 2px 8px;
    border-radius: 4px;
    color: var(--text-muted);
}
.dl-card .dl-size { font-size: 0.75rem; color: var(--text-muted); }
.dl-card .btn-download {
    border: 1.5px solid var(--primary);
    color: var(--primary);
    background: #fff;
    border-radius: 6px;
    padding: 5px 16px;
    cursor: pointer;
    font-size: 0.8rem;
    font-weight: 600;
    transition: var(--transition);
}
.dl-card .btn-download:hover {
    background: var(--primary);
    color: #fff;
}

/* 题库难度颜色 */
.level-easy { color: #52c41a; }
.level-medium { color: #f59e0b; }
.level-hard { color: #e53e3e; }

/* 收藏课程卡片 */
.course-card-icon {
    height: 140px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    color: #fff;
}
.course-card-body { padding: 16px; }
.course-card-body h3 {
    font-size: 1rem;
    color: var(--text-primary);
    margin-bottom: 6px;
}
.course-card-body p {
    font-size: 0.82rem;
    color: var(--text-muted);
    margin-bottom: 10px;
}
.course-card-meta {
    display: flex;
    gap: 14px;
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 10px;
}
.course-card-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: 0.78rem;
    color: var(--text-muted);
    border-top: 1px solid var(--border-light);
    padding-top: 10px;
}
.course-card-btn {
    color: var(--primary);
    font-weight: 600;
}

/* AI IDE 页面 */
.ide-features {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 16px;
    margin-bottom: 32px;
}
.ide-feature {
    background: #fff;
    border-radius: var(--radius-md);
    padding: 24px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}
.ide-feature:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}
.ide-feature .ficon {
    font-size: 2.6rem;
    display: block;
    margin-bottom: 10px;
}
.ide-feature h4 { color: var(--text-primary); margin-bottom: 6px; }
.ide-feature p { color: var(--text-muted); font-size: 0.85rem; margin: 0; }
.ide-editor {
    background: #1e1e1e;
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-md);
}
.ide-editor-header {
    background: #2d2d2d;
    padding: 10px 16px;
    display: flex;
    align-items: center;
    gap: 8px;
}
.ide-dot { width: 10px; height: 10px; border-radius: 50%; display: inline-block; }
.ide-editor-body {
    padding: 20px;
    min-height: 260px;
    font-family: 'Fira Code', 'Consolas', monospace;
    color: #d4d4d4;
    font-size: 0.9rem;
    line-height: 1.8;
}
.ide-editor-body code { color: #ce9178; }
.ide-editor-body .keyword { color: #569cd6; }
.ide-editor-body .string { color: #ce9178; }
.ide-editor-body .comment { color: #6a9955; }
.ide-btn {
    border: none;
    padding: 12px 32px;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 700;
    cursor: pointer;
    transition: all .2s;
    text-decoration: none;
    display: inline-block;
}
.ide-btn-primary {
    background: linear-gradient(135deg, #3b82f6, #2563eb);
    color: #fff;
    box-shadow: 0 4px 12px rgba(59, 130, 246, .3);
}
.ide-btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 6px 16px rgba(59, 130, 246, .4);
}

/* 新风格响应式 */
@media (max-width: 768px) {
    .ide-features { grid-template-columns: repeat(2, 1fr); }
}

/* 在线工具面板 */
.tool-card { position: relative; }
.tool-badge {
    position: absolute;
    top: 10px;
    right: 10px;
    background: #f0f2f5;
    color: var(--text-muted);
    font-size: 0.65rem;
    padding: 2px 8px;
    border-radius: 10px;
}
.tool-panels {
    margin-top: 32px;
    display: grid;
    gap: 20px;
}
.tool-panel {
    background: #fff;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
    border: 1px solid var(--border-light);
}
.tool-panel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 20px;
    background: #f8f9fa;
    border-bottom: 1px solid var(--border-light);
    font-weight: 600;
    color: var(--text-primary);
}
.tool-close {
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    font-size: 1rem;
    padding: 4px;
}
.tool-close:hover { color: var(--danger); }
.tool-panel-body { padding: 20px; }
.tool-panel-body label {
    display: block;
    font-size: 0.82rem;
    color: var(--text-secondary);
    margin-bottom: 6px;
    margin-top: 12px;
    font-weight: 500;
}
.tool-panel-body label:first-child { margin-top: 0; }
.tool-textarea {
    width: 100%;
    min-height: 140px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 12px;
    font-family: 'Consolas', monospace;
    font-size: 0.88rem;
    resize: vertical;
    outline: none;
    background: var(--bg-body);
    color: var(--text-primary);
}
.tool-textarea:focus { border-color: var(--primary); }
.tool-textarea-lg { min-height: 200px; }
.tool-input {
    width: 100%;
    height: 40px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 0 12px;
    font-size: 0.9rem;
    outline: none;
    background: var(--bg-body);
    color: var(--text-primary);
    margin-bottom: 10px;
}
.tool-input:focus { border-color: var(--primary); }
.tool-cols {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}
.tool-actions {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-top: 14px;
    flex-wrap: wrap;
}
.tool-actions .btn { padding: 8px 20px; }
.tool-msg { font-size: 0.82rem; color: var(--success); }
.tool-msg.error { color: var(--danger); }
.tool-btn-full { width: 100%; margin: 10px 0; }
.cc-stats {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 12px;
    margin-top: 16px;
}
.cc-stat {
    background: var(--bg-body);
    border-radius: var(--radius-sm);
    padding: 16px;
    text-align: center;
}
.cc-num { font-size: 1.6rem; font-weight: 700; color: var(--primary); display: block; }
.cc-label { font-size: 0.78rem; color: var(--text-muted); }

@media (max-width: 768px) {
    .tool-cols { grid-template-columns: 1fr; }
    .cc-stats { grid-template-columns: repeat(3, 1fr); }
}

/* 账号设置页 */
.settings-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    max-width: 960px;
}
.settings-title {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 18px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border-light);
}
.settings-title i { color: var(--primary); }
.settings-grid .form-group { margin-bottom: 16px; }
.settings-grid .form-group label {
    display: block;
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 6px;
    font-weight: 500;
}
.settings-grid .form-input {
    width: 100%;
    height: 42px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 0 14px;
    font-size: 0.9rem;
    outline: none;
    background: var(--bg-body);
    color: var(--text-primary);
    transition: var(--transition);
}
.settings-grid .form-input:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(255,107,0,0.08); }
.settings-grid .form-input:disabled { background: #f0f2f5; color: var(--text-muted); cursor: not-allowed; }

/* 通用提示框 */
.alert {
    padding: 12px 16px;
    border-radius: var(--radius-sm);
    margin-bottom: 16px;
    font-size: 0.88rem;
    display: flex;
    align-items: center;
    gap: 8px;
}
.alert-success {
    background: #f6ffed;
    border: 1px solid #b7eb8f;
    color: #389e0d;
}
.alert-error {
    background: #fff2f0;
    border: 1px solid #ffa39e;
    color: #cf1322;
}

@media (max-width: 768px) {
    .settings-grid { grid-template-columns: 1fr; }
}

/* 关于我们 / 联系我们 */
.about-content p {
    color: var(--text-secondary);
    line-height: 2;
    margin-bottom: 12px;
}
.about-cards {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 16px;
}
.about-item {
    text-align: center;
    padding: 20px 12px;
    background: var(--bg-body);
    border-radius: var(--radius-sm);
}
.about-ico { font-size: 2rem; display: block; margin-bottom: 8px; }
.about-item h4 { color: var(--text-primary); margin-bottom: 6px; font-size: 0.95rem; }
.about-item p { color: var(--text-muted); font-size: 0.82rem; margin: 0; }
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    max-width: 960px;
}
.contact-grid .form-group { margin-bottom: 16px; }
.contact-grid .form-group label {
    display: block;
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 6px;
    font-weight: 500;
}
.contact-grid .form-input {
    width: 100%;
    height: 42px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 0 14px;
    font-size: 0.9rem;
    outline: none;
    background: var(--bg-body);
    color: var(--text-primary);
    transition: var(--transition);
}
.contact-grid .form-input:focus { border-color: var(--primary); }
.form-textarea { height: auto; min-height: 120px; padding: 12px 14px; resize: vertical; }
.contact-item {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 14px 0;
    border-bottom: 1px solid var(--border-light);
}
.contact-item:last-child { border-bottom: none; }
.contact-ico {
    width: 44px;
    height: 44px;
    border-radius: 10px;
    background: #fff7f0;
    color: var(--primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    flex-shrink: 0;
}
.contact-item h4 { color: var(--text-primary); font-size: 0.9rem; margin-bottom: 2px; }
.contact-item p { color: var(--text-muted); font-size: 0.85rem; margin: 0; }

@media (max-width: 768px) {
    .about-cards { grid-template-columns: repeat(2, 1fr); }
    .contact-grid { grid-template-columns: 1fr; }
}

/* 实战项目详情页 */
.pr-tag {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: #f0f2f5;
    color: var(--text-secondary);
    font-size: 0.8rem;
    padding: 5px 14px;
    border-radius: 20px;
}
.pr-tag i { color: var(--primary); }
.practice-steps {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}
.pstep {
    display: flex;
    gap: 14px;
    align-items: flex-start;
    background: var(--bg-body);
    border-radius: var(--radius-sm);
    padding: 18px;
    transition: var(--transition);
}
.pstep:hover { transform: translateY(-2px); box-shadow: var(--shadow-sm); }
.pstep-num {
    width: 34px;
    height: 34px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), #ff9a3c);
    color: #fff;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}
.pstep-body h4 { color: var(--text-primary); font-size: 0.95rem; margin-bottom: 4px; }
.pstep-body p { color: var(--text-muted); font-size: 0.82rem; margin: 0; line-height: 1.6; }

@media (max-width: 768px) {
    .practice-steps { grid-template-columns: 1fr; }
}

/* ===== 按难度分组课程列表（参考 W3Cschool 设计） ===== */
.empty-state {
    text-align: center;
    padding: 80px 20px;
    color: var(--text-muted);
}
.empty-state i {
    font-size: 3rem;
    margin-bottom: 16px;
    display: block;
}
.empty-state p { font-size: 0.95rem; }

.diff-group {
    background: #fff;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    padding: 24px;
    margin-bottom: 20px;
}
.diff-group-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 18px;
    padding-bottom: 14px;
    border-bottom: 2px solid #f5f5f5;
}
.diff-title {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-primary);
    position: relative;
    padding-left: 12px;
}
.diff-title::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 4px;
    height: 18px;
    background: var(--primary);
    border-radius: 2px;
}
.learn-path-link {
    font-size: 0.85rem;
    color: var(--primary);
    font-weight: 500;
    text-decoration: none;
    transition: var(--transition);
}
.learn-path-link:hover {
    color: var(--primary-dark);
    transform: translateX(3px);
}
.diff-group-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 16px;
}

/* 课程卡片 V2（彩色封面版） */
.course-card-v2 {
    display: flex;
    flex-direction: column;
    background: #fff;
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    text-decoration: none;
    color: inherit;
    border: 1px solid var(--border-light);
    transition: var(--transition);
}
.course-card-v2:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary);
}
.cv-banner {
    height: 130px;
    background: linear-gradient(135deg, var(--card-color, #ff6b00) 0%, color-mix(in srgb, var(--card-color, #ff6b00) 75%, #000) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}
.cv-banner::before {
    content: '';
    position: absolute;
    right: -30px;
    top: -30px;
    width: 120px;
    height: 120px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
}
.cv-banner::after {
    content: '';
    position: absolute;
    left: -40px;
    bottom: -40px;
    width: 100px;
    height: 100px;
    background: rgba(255, 255, 255, 0.08);
    border-radius: 50%;
}
.cv-icon {
    font-size: 3rem;
    position: relative;
    z-index: 1;
    filter: drop-shadow(0 2px 4px rgba(0,0,0,0.15));
}
.cv-corner {
    position: absolute;
    top: 10px;
    right: -28px;
    background: #ff4d4f;
    color: #fff;
    font-size: 0.7rem;
    padding: 3px 30px;
    transform: rotate(35deg);
    font-weight: 600;
    box-shadow: 0 2px 6px rgba(255, 77, 79, 0.3);
    z-index: 2;
}
.cv-students {
    position: absolute;
    bottom: 8px;
    left: 10px;
    color: rgba(255, 255, 255, 0.95);
    font-size: 0.72rem;
    background: rgba(0, 0, 0, 0.25);
    padding: 2px 8px;
    border-radius: 10px;
    z-index: 2;
}
.cv-body {
    padding: 14px;
    flex: 1;
    display: flex;
    flex-direction: column;
}
.cv-title {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 6px;
    line-height: 1.4;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 1;
    -webkit-box-orient: vertical;
}
.cv-desc {
    font-size: 0.8rem;
    color: var(--text-muted);
    line-height: 1.5;
    margin-bottom: 10px;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    flex: 1;
}
.cv-foot {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.75rem;
    color: var(--text-muted);
    padding-top: 8px;
    border-top: 1px dashed var(--border-light);
}
.cv-meta {
    display: flex;
    align-items: center;
    gap: 4px;
}
.cv-meta i { color: var(--primary); }
.cv-progress {
    color: var(--primary);
    font-weight: 600;
}

@media (max-width: 992px) {
    .diff-group-grid { grid-template-columns: repeat(auto-fill, minmax(180px, 1fr)); }
}
@media (max-width: 480px) {
    .diff-group-grid { grid-template-columns: 1fr 1fr; }
    .cv-banner { height: 100px; }
    .cv-icon { font-size: 2.2rem; }
}

/* ===== 首页升级样式 ===== */

/* 平台数据统计条 */
.stats-strip {
    background: linear-gradient(135deg, #1e3c72 0%, #2a5298 100%);
    color: #fff;
    padding: 26px 0;
    margin-top: 0;
}
.stats-inner {
    display: flex;
    align-items: center;
    gap: 36px;
    flex-wrap: wrap;
}
.stat-box {
    text-align: center;
    flex-shrink: 0;
}
.stat-value {
    font-size: 1.9rem;
    font-weight: 700;
    display: block;
    line-height: 1.2;
    background: linear-gradient(135deg, #ffd700, #ff9a3c);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}
.stat-label {
    font-size: 0.82rem;
    opacity: 0.85;
    display: block;
    margin-top: 2px;
}
.stats-inner .stat-box + .stat-box {
    border-left: 1px solid rgba(255,255,255,0.15);
    padding-left: 36px;
}
.stat-cta {
    margin-left: auto;
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}
.btn-ghost {
    background: rgba(255,255,255,0.15);
    color: #fff;
    border: 1px solid rgba(255,255,255,0.35);
    padding: 9px 22px;
    border-radius: 22px;
    font-size: 0.88rem;
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 6px;
}
.btn-ghost:hover {
    background: rgba(255,255,255,0.28);
    transform: translateY(-2px);
}
.btn-primary-light {
    background: linear-gradient(135deg, #ff6b00, #ff9a3c);
    color: #fff;
    padding: 9px 22px;
    border-radius: 22px;
    font-size: 0.88rem;
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 6px;
    box-shadow: 0 4px 12px rgba(255,107,0,0.3);
}
.btn-primary-light:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(255,107,0,0.4);
}

/* 轮播装饰卡片 */
.banner-kicker {
    display: inline-block;
    background: rgba(255,255,255,0.2);
    color: #fff;
    font-size: 0.8rem;
    padding: 3px 12px;
    border-radius: 14px;
    margin-bottom: 12px;
    font-weight: 500;
}
.banner-text .btn-banner {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: #fff;
    color: #333;
    border-radius: 20px;
    padding: 8px 22px;
    font-size: 0.85rem;
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition);
    box-shadow: 0 2px 8px rgba(0,0,0,0.15);
}
.banner-text .btn-banner:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 14px rgba(0,0,0,0.2);
}
.decor-card {
    width: 280px;
    height: 200px;
    background: rgba(255,255,255,0.15);
    border: 1px solid rgba(255,255,255,0.3);
    border-radius: 16px;
    backdrop-filter: blur(6px);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 10px;
    box-shadow: 0 8px 24px rgba(0,0,0,0.15);
}
.decor-emoji {
    font-size: 4rem;
    filter: drop-shadow(0 4px 8px rgba(0,0,0,0.2));
}
.decor-tag {
    background: rgba(0,0,0,0.3);
    color: #fff;
    font-size: 0.78rem;
    padding: 4px 16px;
    border-radius: 14px;
}

/* 课程 tab 过滤 */
.course-grid .course-card { transition: var(--transition); }
.course-grid .course-card.filter-hidden { display: none; }
.empty-courses {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-muted);
}
.empty-courses i { font-size: 3rem; margin-bottom: 16px; display: block; }

/* 响应式 */
@media (max-width: 768px) {
    .stats-inner { gap: 20px; }
    .stats-inner .stat-box + .stat-box { padding-left: 20px; }
    .stat-value { font-size: 1.5rem; }
    .stat-cta { margin-left: 0; width: 100%; justify-content: center; }
    .decor-card { width: 200px; height: 150px; }
    .decor-emoji { font-size: 3rem; }
}
@media (max-width: 480px) {
    .stats-inner { justify-content: center; }
    .decor-card { display: none; }
}

/* 收藏按钮 active 状态 */
.btn-favorite.active {
    border-color: #ff4d4f;
    color: #ff4d4f;
    background: #fff5f5;
}
.btn-favorite.active i { color: #ff4d4f; }

/* AI IDE 在线编辑器 */
.ide-lang-select {
    background: #3c3c3c;
    color: #d4d4d4;
    border: 1px solid #555;
    border-radius: 6px;
    padding: 4px 10px;
    font-size: 0.82rem;
    margin-left: 12px;
    outline: none;
    font-family: 'Consolas', monospace;
}
.ide-code {
    width: 100%;
    min-height: 300px;
    background: transparent;
    border: none;
    outline: none;
    resize: vertical;
    color: #d4d4d4;
    font-family: 'Fira Code', 'Consolas', monospace;
    font-size: 0.9rem;
    line-height: 1.8;
    padding: 0;
    caret-color: #fff;
}
.ide-runbar {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}
.ide-btn-reset {
    background: #f0f2f5;
    color: var(--text-secondary);
    box-shadow: none;
}
.ide-btn-reset:hover {
    background: #e2e6ea;
    transform: translateY(-1px);
}
.ide-run-msg { font-size: 0.85rem; }
.ide-run-msg.ok { color: #52c41a; }
.ide-run-msg.err { color: #e53e3e; }
.ide-output {
    background: #1e1e1e;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 20px rgba(0,0,0,.15);
    margin-bottom: 16px;
}
.ide-output-header {
    background: #2d2d2d;
    padding: 10px 16px;
    color: #aaa;
    font-size: 0.82rem;
    border-bottom: 1px solid #3c3c3c;
}
.ide-output-body {
    padding: 16px;
    min-height: 120px;
    color: #d4d4d4;
    font-family: 'Fira Code', 'Consolas', monospace;
    font-size: 0.88rem;
    line-height: 1.7;
    margin: 0;
    white-space: pre-wrap;
    word-break: break-word;
}

/* Markdown 预览 */
.md-preview {
    min-height: 200px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 16px;
    background: var(--bg-body);
    color: var(--text-primary);
    font-size: 0.9rem;
    line-height: 1.8;
    overflow: auto;
}
.md-preview h1 { font-size: 1.4rem; margin: 8px 0; }
.md-preview h2 { font-size: 1.2rem; margin: 8px 0; }
.md-preview h3 { font-size: 1.05rem; margin: 6px 0; }
.md-preview ul { padding-left: 20px; margin: 8px 0; }
.md-preview li { margin: 2px 0; }
.md-preview code {
    background: #f0f2f5;
    padding: 2px 5px;
    border-radius: 3px;
    font-family: 'Consolas', monospace;
    color: var(--primary);
    font-size: 0.85em;
}
.md-preview pre.md-code {
    background: #282c34;
    color: #abb2bf;
    padding: 12px;
    border-radius: 8px;
    overflow: auto;
    margin: 8px 0;
}
.md-preview pre.md-code code { background: transparent; color: inherit; padding: 0; }

/* 颜色选择器 */
.tool-color-picker {
    width: 100%;
    height: 60px;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    padding: 0;
    background: none;
}
.color-swatches {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 8px;
    margin-top: 12px;
}
.color-swatch {
    height: 32px;
    border-radius: 6px;
    cursor: pointer;
    border: 1px solid rgba(0,0,0,0.08);
    transition: transform 0.15s;
}
.color-swatch:hover { transform: scale(1.1); }
.color-value {
    padding: 10px 12px;
    background: var(--bg-body);
    border-radius: var(--radius-sm);
    font-family: 'Consolas', monospace;
    font-size: 0.85rem;
    margin-bottom: 8px;
    cursor: pointer;
    border: 1px dashed var(--border-color);
    transition: var(--transition);
}
.color-value:hover { border-color: var(--primary); color: var(--primary); }
.color-preview {
    height: 70px;
    border-radius: var(--radius-sm);
    background: #ff6b00;
    border: 1px solid rgba(0,0,0,0.08);
}

/* 正则测试 */
.regex-result { margin-top: 14px; }
.regex-yes {
    background: #f6ffed;
    border: 1px solid #b7eb8f;
    color: #389e0d;
    padding: 8px 14px;
    border-radius: 6px;
    font-size: 0.85rem;
    margin-bottom: 10px;
}
.regex-no {
    background: #fff7e6;
    border: 1px solid #ffd591;
    color: #d46b08;
    padding: 8px 14px;
    border-radius: 6px;
    font-size: 0.85rem;
}
.regex-matches { display: flex; flex-wrap: wrap; gap: 8px; }
.regex-match {
    background: #e6f7ff;
    border: 1px solid #91d5ff;
    color: #1890ff;
    padding: 2px 10px;
    border-radius: 4px;
    font-family: 'Consolas', monospace;
    font-size: 0.8rem;
}

/* 新风格响应式 */
@media (max-width: 768px) {
    .header .header-inner { flex-wrap: wrap; gap: 10px; }
    .header-search { max-width: 100%; width: 100%; order: 3; margin-left: 0; }
    .page-banner { padding: 32px 0; }
    .page-banner h1 { font-size: 1.5rem; }
    .main-nav .nav-list a { padding: 11px 10px; font-size: 0.85rem; }
    .tool-grid, .tutorial-grid { grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); }
    .dl-grid { grid-template-columns: 1fr; }
    .topbar-left { display: none; }
    .topbar-inner { justify-content: flex-end; }
}