/* ========================================
   海角 - 主样式文件
   ziyunlongtech.cn
   ======================================== */

/* CSS变量 */
:root {
    --primary: #0d2b5e;
    --primary-light: #1a4080;
    --accent: #e8503a;
    --accent-light: #f07060;
    --bg-dark: #0a1628;
    --bg-medium: #112240;
    --bg-light: #f5f7fa;
    --text-dark: #1a1a2e;
    --text-medium: #4a5568;
    --text-light: #718096;
    --white: #ffffff;
    --border: #e2e8f0;
    --shadow: 0 4px 20px rgba(13,43,94,0.12);
    --shadow-hover: 0 8px 30px rgba(13,43,94,0.2);
    --radius: 12px;
    --radius-sm: 6px;
    --transition: all 0.3s ease;
    --font-main: 'PingFang SC', 'Microsoft YaHei', '微软雅黑', 'Helvetica Neue', Arial, sans-serif;
}

/* 重置样式 */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-main);
    color: var(--text-dark);
    background: var(--white);
    line-height: 1.7;
    overflow-x: hidden;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

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

ul, ol {
    list-style: none;
}

/* ========================================
   顶部公告栏
   ======================================== */
.top-bar {
    background: var(--primary);
    color: rgba(255,255,255,0.85);
    font-size: 13px;
    padding: 6px 0;
    text-align: center;
}

.top-bar a {
    color: var(--accent-light);
    margin: 0 8px;
}

.top-bar a:hover {
    color: var(--white);
}

/* ========================================
   头部导航
   ======================================== */
.site-header {
    background: var(--white);
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-inner {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    align-items: center;
    height: 70px;
    gap: 30px;
}

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

.site-logo img.logo-img {
    height: 44px;
    width: auto;
}

.site-logo .logo-text {
    font-size: 22px;
    font-weight: 800;
    color: var(--primary);
    letter-spacing: -0.5px;
}

.site-logo .logo-text span {
    color: var(--accent);
}

/* 主导航 */
.main-nav {
    flex: 1;
    display: flex;
    align-items: center;
}

.nav-list {
    display: flex;
    align-items: center;
    gap: 4px;
}

.nav-list > li {
    position: relative;
}

.nav-list > li > a {
    display: flex;
    align-items: center;
    gap: 4px;
    padding: 8px 14px;
    font-size: 15px;
    font-weight: 500;
    color: var(--text-dark);
    border-radius: var(--radius-sm);
    transition: var(--transition);
}

.nav-list > li > a:hover,
.nav-list > li > a.active {
    color: var(--accent);
    background: rgba(232,80,58,0.06);
}

.nav-list > li > a .nav-arrow {
    font-size: 10px;
    transition: transform 0.3s;
}

.nav-list > li:hover > a .nav-arrow {
    transform: rotate(180deg);
}

/* 下拉菜单 */
.dropdown {
    position: absolute;
    top: calc(100% + 8px);
    left: 0;
    min-width: 160px;
    background: var(--white);
    border-radius: var(--radius);
    box-shadow: 0 8px 30px rgba(0,0,0,0.12);
    border: 1px solid var(--border);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: var(--transition);
    z-index: 100;
}

.nav-list > li:hover .dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown a {
    display: block;
    padding: 10px 16px;
    font-size: 14px;
    color: var(--text-medium);
    border-radius: 0;
    transition: var(--transition);
}

.dropdown a:hover {
    color: var(--accent);
    background: var(--bg-light);
    padding-left: 22px;
}

.dropdown li:first-child a {
    border-radius: var(--radius) var(--radius) 0 0;
}

.dropdown li:last-child a {
    border-radius: 0 0 var(--radius) var(--radius);
}

/* 搜索框 */
.header-search {
    display: flex;
    align-items: center;
    background: var(--bg-light);
    border: 1.5px solid var(--border);
    border-radius: 24px;
    padding: 6px 14px;
    gap: 8px;
    min-width: 220px;
    transition: var(--transition);
}

.header-search:focus-within {
    border-color: var(--accent);
    background: var(--white);
    box-shadow: 0 0 0 3px rgba(232,80,58,0.1);
}

.header-search input {
    border: none;
    background: transparent;
    font-size: 14px;
    color: var(--text-dark);
    outline: none;
    flex: 1;
    font-family: var(--font-main);
}

.header-search input::placeholder {
    color: var(--text-light);
}

.header-search button {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-light);
    font-size: 16px;
    padding: 0;
    transition: var(--transition);
}

.header-search button:hover {
    color: var(--accent);
}

/* 汉堡菜单 */
.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 4px;
    background: none;
    border: none;
}

.hamburger span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--primary);
    border-radius: 2px;
    transition: var(--transition);
}

/* ========================================
   面包屑
   ======================================== */
.breadcrumb {
    background: var(--bg-light);
    padding: 10px 0;
    border-bottom: 1px solid var(--border);
}

.breadcrumb-inner {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 13px;
    color: var(--text-light);
}

.breadcrumb-inner a {
    color: var(--text-light);
}

.breadcrumb-inner a:hover {
    color: var(--accent);
}

.breadcrumb-inner .sep {
    color: var(--border);
}

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

/* ========================================
   Hero Banner
   ======================================== */
.hero-section {
    position: relative;
    height: 580px;
    overflow: hidden;
    background: var(--bg-dark);
}

.hero-bg {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0.55;
}

.hero-overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(10,22,40,0.85) 0%, rgba(13,43,94,0.6) 50%, rgba(232,80,58,0.2) 100%);
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 20px;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: rgba(232,80,58,0.2);
    border: 1px solid rgba(232,80,58,0.4);
    color: var(--accent-light);
    font-size: 13px;
    padding: 5px 14px;
    border-radius: 20px;
    margin-bottom: 18px;
    width: fit-content;
}

.hero-content h1 {
    font-size: clamp(32px, 5vw, 52px);
    font-weight: 900;
    color: var(--white);
    line-height: 1.2;
    margin-bottom: 16px;
    text-shadow: 0 2px 10px rgba(0,0,0,0.3);
}

.hero-content h1 .highlight {
    color: var(--accent-light);
}

.hero-desc {
    font-size: 17px;
    color: rgba(255,255,255,0.8);
    max-width: 560px;
    margin-bottom: 32px;
    line-height: 1.7;
}

.hero-actions {
    display: flex;
    gap: 14px;
    flex-wrap: wrap;
}

.btn-primary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: var(--accent);
    color: var(--white);
    padding: 13px 28px;
    border-radius: 30px;
    font-size: 15px;
    font-weight: 600;
    transition: var(--transition);
    border: 2px solid var(--accent);
}

.btn-primary:hover {
    background: var(--accent-light);
    border-color: var(--accent-light);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(232,80,58,0.4);
    color: var(--white);
}

.btn-outline {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: transparent;
    color: var(--white);
    padding: 13px 28px;
    border-radius: 30px;
    font-size: 15px;
    font-weight: 600;
    border: 2px solid rgba(255,255,255,0.5);
    transition: var(--transition);
}

.btn-outline:hover {
    background: rgba(255,255,255,0.1);
    border-color: var(--white);
    transform: translateY(-2px);
    color: var(--white);
}

.hero-stats {
    position: absolute;
    bottom: 30px;
    right: 40px;
    display: flex;
    gap: 30px;
}

.stat-item {
    text-align: center;
    color: var(--white);
}

.stat-item .num {
    font-size: 28px;
    font-weight: 800;
    color: var(--accent-light);
    display: block;
}

.stat-item .label {
    font-size: 12px;
    opacity: 0.75;
}

/* ========================================
   通用容器
   ======================================== */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 20px;
}

.section {
    padding: 70px 0;
}

.section-alt {
    background: var(--bg-light);
}

.section-dark {
    background: var(--bg-dark);
    color: var(--white);
}

.section-title {
    text-align: center;
    margin-bottom: 50px;
}

.section-title .tag {
    display: inline-block;
    background: rgba(232,80,58,0.1);
    color: var(--accent);
    font-size: 13px;
    font-weight: 600;
    padding: 4px 14px;
    border-radius: 20px;
    margin-bottom: 12px;
    letter-spacing: 1px;
    text-transform: uppercase;
}

.section-title h2 {
    font-size: clamp(24px, 3.5vw, 36px);
    font-weight: 800;
    color: var(--primary);
    margin-bottom: 12px;
    line-height: 1.3;
}

.section-dark .section-title h2 {
    color: var(--white);
}

.section-title p {
    font-size: 16px;
    color: var(--text-medium);
    max-width: 600px;
    margin: 0 auto;
}

.section-dark .section-title p {
    color: rgba(255,255,255,0.7);
}

/* ========================================
   视频卡片
   ======================================== */
.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
}

.video-card {
    background: var(--white);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
    cursor: pointer;
}

.video-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-hover);
}

.video-thumb {
    position: relative;
    aspect-ratio: 16/9;
    overflow: hidden;
    background: var(--bg-dark);
}

.video-thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.4s ease;
}

.video-card:hover .video-thumb img {
    transform: scale(1.06);
}

.video-play-btn {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(0,0,0,0);
    transition: var(--transition);
}

.video-card:hover .video-play-btn {
    background: rgba(0,0,0,0.35);
}

.play-icon {
    width: 56px;
    height: 56px;
    background: var(--accent);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transform: scale(0.7);
    transition: var(--transition);
    box-shadow: 0 4px 20px rgba(232,80,58,0.5);
}

.video-card:hover .play-icon {
    opacity: 1;
    transform: scale(1);
}

.play-icon::after {
    content: '';
    border-style: solid;
    border-width: 10px 0 10px 18px;
    border-color: transparent transparent transparent var(--white);
    margin-left: 4px;
}

.video-duration {
    position: absolute;
    bottom: 8px;
    right: 8px;
    background: rgba(0,0,0,0.75);
    color: var(--white);
    font-size: 12px;
    padding: 2px 7px;
    border-radius: 4px;
}

.video-tag {
    position: absolute;
    top: 8px;
    left: 8px;
    background: var(--accent);
    color: var(--white);
    font-size: 11px;
    font-weight: 600;
    padding: 3px 9px;
    border-radius: 4px;
}

.video-info {
    padding: 14px 16px;
}

.video-info h3 {
    font-size: 15px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 8px;
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.video-meta {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 13px;
    color: var(--text-light);
}

.video-meta span {
    display: flex;
    align-items: center;
    gap: 4px;
}

/* ========================================
   特色模块
   ======================================== */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 24px;
}

.feature-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 28px 24px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border: 1px solid var(--border);
    text-align: center;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
    border-color: rgba(232,80,58,0.2);
}

.feature-icon {
    width: 64px;
    height: 64px;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    margin: 0 auto 18px;
    color: var(--white);
}

.feature-card h3 {
    font-size: 17px;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 10px;
}

.feature-card p {
    font-size: 14px;
    color: var(--text-medium);
    line-height: 1.65;
}

/* ========================================
   专家展示
   ======================================== */
.experts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 28px;
}

.expert-card {
    background: var(--white);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.expert-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}

.expert-photo {
    position: relative;
    height: 260px;
    overflow: hidden;
    background: var(--bg-medium);
}

.expert-photo img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: top;
    transition: transform 0.4s ease;
}

.expert-card:hover .expert-photo img {
    transform: scale(1.05);
}

.expert-badge {
    position: absolute;
    top: 12px;
    right: 12px;
    background: var(--accent);
    color: var(--white);
    font-size: 11px;
    font-weight: 600;
    padding: 4px 10px;
    border-radius: 20px;
}

.expert-info {
    padding: 18px 20px;
}

.expert-info h3 {
    font-size: 18px;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 4px;
}

.expert-title {
    font-size: 13px;
    color: var(--accent);
    font-weight: 500;
    margin-bottom: 10px;
}

.expert-desc {
    font-size: 13px;
    color: var(--text-medium);
    line-height: 1.6;
    margin-bottom: 14px;
}

.expert-actions {
    display: flex;
    gap: 8px;
}

.btn-sm {
    padding: 7px 14px;
    font-size: 13px;
    border-radius: 20px;
    font-weight: 500;
    transition: var(--transition);
    cursor: pointer;
    border: 1.5px solid;
}

.btn-sm-primary {
    background: var(--accent);
    color: var(--white);
    border-color: var(--accent);
}

.btn-sm-primary:hover {
    background: var(--accent-light);
    border-color: var(--accent-light);
    color: var(--white);
}

.btn-sm-outline {
    background: transparent;
    color: var(--primary);
    border-color: var(--primary);
}

.btn-sm-outline:hover {
    background: var(--primary);
    color: var(--white);
}

/* ========================================
   合作品牌Logo墙
   ======================================== */
.partners-row {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    justify-content: center;
    align-items: center;
}

.partner-logo {
    background: var(--white);
    border: 1.5px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 14px 24px;
    font-size: 15px;
    font-weight: 700;
    color: var(--text-medium);
    transition: var(--transition);
    min-width: 120px;
    text-align: center;
}

.partner-logo:hover {
    border-color: var(--accent);
    color: var(--accent);
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

/* ========================================
   FAQ
   ======================================== */
.faq-list {
    max-width: 820px;
    margin: 0 auto;
}

.faq-item {
    border: 1.5px solid var(--border);
    border-radius: var(--radius);
    margin-bottom: 14px;
    overflow: hidden;
    transition: var(--transition);
}

.faq-item.open {
    border-color: rgba(232,80,58,0.3);
    box-shadow: 0 4px 16px rgba(232,80,58,0.08);
}

.faq-question {
    padding: 18px 22px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    font-size: 15px;
    font-weight: 600;
    color: var(--text-dark);
    background: var(--white);
    transition: var(--transition);
    user-select: none;
}

.faq-question:hover {
    color: var(--accent);
}

.faq-item.open .faq-question {
    color: var(--accent);
    background: rgba(232,80,58,0.03);
}

.faq-icon {
    width: 24px;
    height: 24px;
    background: var(--bg-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    flex-shrink: 0;
    transition: var(--transition);
    color: var(--text-medium);
}

.faq-item.open .faq-icon {
    background: var(--accent);
    color: var(--white);
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.35s ease, padding 0.35s ease;
    padding: 0 22px;
    font-size: 14px;
    color: var(--text-medium);
    line-height: 1.75;
}

.faq-item.open .faq-answer {
    max-height: 300px;
    padding: 0 22px 18px;
}

/* ========================================
   用户评价
   ======================================== */
.reviews-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 22px;
}

.review-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 22px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
    transition: var(--transition);
}

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

.review-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 14px;
}

.reviewer-avatar {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    color: var(--white);
    font-weight: 700;
    flex-shrink: 0;
}

.reviewer-info h4 {
    font-size: 15px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 2px;
}

.reviewer-info span {
    font-size: 12px;
    color: var(--text-light);
}

.review-stars {
    color: #f59e0b;
    font-size: 14px;
    margin-bottom: 10px;
}

.review-text {
    font-size: 14px;
    color: var(--text-medium);
    line-height: 1.7;
}

/* ========================================
   联系我们
   ======================================== */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    align-items: start;
}

.contact-info h3 {
    font-size: 22px;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 20px;
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: 14px;
    margin-bottom: 18px;
}

.contact-item-icon {
    width: 42px;
    height: 42px;
    background: rgba(232,80,58,0.1);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    flex-shrink: 0;
    color: var(--accent);
}

.contact-item-text h4 {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 3px;
}

.contact-item-text p {
    font-size: 14px;
    color: var(--text-medium);
}

.contact-qr-area {
    display: flex;
    gap: 24px;
    flex-wrap: wrap;
}

.qr-box {
    text-align: center;
}

.qr-box img {
    width: 130px;
    height: 130px;
    border-radius: var(--radius-sm);
    border: 2px solid var(--border);
    margin-bottom: 8px;
}

.qr-box p {
    font-size: 13px;
    color: var(--text-medium);
    font-weight: 500;
}

/* ========================================
   社交分享
   ======================================== */
.share-bar {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}

.share-label {
    font-size: 14px;
    color: var(--text-medium);
    font-weight: 500;
}

.share-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    color: var(--white);
}

.share-wechat { background: #07c160; }
.share-weibo { background: #e6162d; }
.share-douyin { background: #010101; }
.share-bilibili { background: #00a1d6; }

.share-btn:hover {
    opacity: 0.85;
    transform: translateY(-2px);
}

/* ========================================
   页脚
   ======================================== */
.site-footer {
    background: var(--bg-dark);
    color: rgba(255,255,255,0.75);
    padding: 60px 0 0;
}

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

.footer-brand .footer-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 16px;
}

.footer-brand .footer-logo img {
    height: 38px;
    filter: brightness(0) invert(1);
}

.footer-brand .footer-logo span {
    font-size: 20px;
    font-weight: 800;
    color: var(--white);
}

.footer-brand p {
    font-size: 14px;
    line-height: 1.7;
    margin-bottom: 20px;
    color: rgba(255,255,255,0.6);
}

.footer-col h4 {
    font-size: 15px;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 16px;
    padding-bottom: 8px;
    border-bottom: 2px solid rgba(232,80,58,0.4);
}

.footer-col ul li {
    margin-bottom: 8px;
}

.footer-col ul li a {
    font-size: 14px;
    color: rgba(255,255,255,0.6);
    transition: var(--transition);
}

.footer-col ul li a:hover {
    color: var(--accent-light);
    padding-left: 4px;
}

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.1);
    padding: 20px 0;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 12px;
    font-size: 13px;
    color: rgba(255,255,255,0.45);
}

.footer-bottom a {
    color: rgba(255,255,255,0.45);
}

.footer-bottom a:hover {
    color: var(--accent-light);
}

.footer-links {
    display: flex;
    gap: 16px;
}

/* ========================================
   How-To指南
   ======================================== */
.howto-steps {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 24px;
    counter-reset: step-counter;
}

.step-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 28px 22px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
    position: relative;
    counter-increment: step-counter;
    transition: var(--transition);
}

.step-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
    border-color: rgba(232,80,58,0.2);
}

.step-num {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    font-weight: 800;
    color: var(--white);
    margin-bottom: 16px;
}

.step-card h3 {
    font-size: 16px;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 8px;
}

.step-card p {
    font-size: 13px;
    color: var(--text-medium);
    line-height: 1.65;
}

/* ========================================
   直播/社区入口
   ======================================== */
.live-section {
    background: linear-gradient(135deg, var(--bg-dark) 0%, var(--bg-medium) 100%);
    padding: 60px 0;
    position: relative;
    overflow: hidden;
}

.live-section::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -10%;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(232,80,58,0.15) 0%, transparent 70%);
    border-radius: 50%;
}

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

.live-card {
    background: rgba(255,255,255,0.06);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: var(--radius);
    padding: 22px 18px;
    text-align: center;
    transition: var(--transition);
    cursor: pointer;
}

.live-card:hover {
    background: rgba(232,80,58,0.15);
    border-color: rgba(232,80,58,0.4);
    transform: translateY(-4px);
}

.live-card .icon {
    font-size: 36px;
    margin-bottom: 12px;
}

.live-card h3 {
    font-size: 15px;
    font-weight: 600;
    color: var(--white);
    margin-bottom: 6px;
}

.live-card p {
    font-size: 12px;
    color: rgba(255,255,255,0.55);
}

.live-badge {
    display: inline-block;
    background: var(--accent);
    color: var(--white);
    font-size: 10px;
    font-weight: 700;
    padding: 2px 7px;
    border-radius: 10px;
    margin-top: 8px;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.6; }
}

/* ========================================
   标签页/Tab
   ======================================== */
.tab-nav {
    display: flex;
    gap: 4px;
    border-bottom: 2px solid var(--border);
    margin-bottom: 28px;
    overflow-x: auto;
}

.tab-btn {
    padding: 10px 20px;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-medium);
    background: none;
    border: none;
    cursor: pointer;
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    white-space: nowrap;
    transition: var(--transition);
    font-family: var(--font-main);
}

.tab-btn:hover {
    color: var(--accent);
}

.tab-btn.active {
    color: var(--accent);
    border-bottom-color: var(--accent);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* ========================================
   响应式
   ======================================== */
@media (max-width: 1024px) {
    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }
    .contact-grid {
        grid-template-columns: 1fr;
    }
    .hero-stats {
        display: none;
    }
}

@media (max-width: 768px) {
    .header-inner {
        flex-wrap: wrap;
        height: auto;
        padding: 12px 20px;
        gap: 12px;
    }
    .main-nav {
        order: 3;
        width: 100%;
        display: none;
    }
    .main-nav.open {
        display: flex;
    }
    .nav-list {
        flex-direction: column;
        width: 100%;
        gap: 0;
    }
    .nav-list > li > a {
        padding: 12px 8px;
        border-radius: 0;
        border-bottom: 1px solid var(--border);
    }
    .dropdown {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        border: none;
        background: var(--bg-light);
        border-radius: 0;
    }
    .hamburger {
        display: flex;
    }
    .header-search {
        min-width: unset;
        flex: 1;
    }
    .hero-section {
        height: 420px;
    }
    .hero-content h1 {
        font-size: 26px;
    }
    .footer-grid {
        grid-template-columns: 1fr;
        gap: 28px;
    }
    .section {
        padding: 48px 0;
    }
    .video-grid {
        grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    }
    .experts-grid {
        grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    }
    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .hero-actions {
        flex-direction: column;
    }
    .btn-primary, .btn-outline {
        width: 100%;
        justify-content: center;
    }
    .reviews-grid {
        grid-template-columns: 1fr;
    }
}

/* ========================================
   工具类
   ======================================== */
.text-center { text-align: center; }
.text-accent { color: var(--accent); }
.text-primary { color: var(--primary); }
.mt-20 { margin-top: 20px; }
.mt-40 { margin-top: 40px; }
.mb-20 { margin-bottom: 20px; }
.mb-40 { margin-bottom: 40px; }

.badge {
    display: inline-block;
    padding: 3px 10px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
}

.badge-hot {
    background: rgba(232,80,58,0.1);
    color: var(--accent);
}

.badge-new {
    background: rgba(16,185,129,0.1);
    color: #10b981;
}

.badge-live {
    background: var(--accent);
    color: var(--white);
    animation: pulse 2s infinite;
}

/* 懒加载占位 */
img[data-src] {
    background: var(--bg-light);
    min-height: 100px;
}

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

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

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

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

/* 视频卡片大图版 */
.video-card-large {
    grid-column: span 2;
}

@media (max-width: 768px) {
    .video-card-large {
        grid-column: span 1;
    }
}

/* 数字统计条 */
.stats-bar {
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    padding: 30px 0;
}

.stats-row {
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
    gap: 20px;
}

.stats-row .stat {
    text-align: center;
    color: var(--white);
}

.stats-row .stat .num {
    font-size: 36px;
    font-weight: 900;
    display: block;
    line-height: 1;
    margin-bottom: 6px;
}

.stats-row .stat .label {
    font-size: 14px;
    opacity: 0.85;
}