/* roulang page: index */
:root {
      --primary-deep: #0B0F19;
      --accent-red: #E63946;
      --accent-red-dark: #C1121F;
      --light-bg: #F1FAEE;
      --ice-blue: #A8DADC;
      --text-dark: #1D1D1D;
      --text-light: #F1FAEE;
      --text-muted: #6B7280;
      --card-bg: #FFFFFF;
      --card-dark-bg: #1A1F2B;
      --border-light: rgba(255,255,255,0.08);
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-md: 0 12px 32px rgba(0,0,0,0.08);
      --radius-md: 16px;
      --radius-sm: 8px;
      --max-width: 1280px;
      --header-height: 76px;
      --transition-smooth: 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    }

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

    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Noto Sans SC", sans-serif;
      background-color: #FFFFFF;
      color: var(--text-dark);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
      scroll-behavior: smooth;
      overflow-x: hidden;
    }

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

    a {
      text-decoration: none;
      color: inherit;
    }

    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 20px;
      width: 100%;
    }
    @media (min-width: 768px) {
      .container { padding: 0 40px; }
    }
    @media (min-width: 1025px) {
      .container { padding: 0 80px; }
    }

    /* 按钮系统 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 14px 32px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 1rem;
      transition: background 0.2s ease, transform 0.2s ease, border-color 0.2s ease;
      cursor: pointer;
      border: 1.5px solid transparent;
      white-space: nowrap;
    }
    .btn-primary {
      background: var(--accent-red);
      color: white;
      border-color: var(--accent-red);
    }
    .btn-primary:hover {
      background: var(--accent-red-dark);
      border-color: var(--accent-red-dark);
      transform: scale(1.03);
    }
    .btn-outline {
      background: transparent;
      border-color: var(--accent-red);
      color: var(--accent-red);
    }
    .btn-outline:hover {
      background: var(--accent-red);
      color: white;
    }
    .btn-light {
      background: white;
      color: var(--primary-deep);
      border-color: white;
    }
    .btn-light:hover {
      background: #e5e7eb;
      border-color: #e5e7eb;
    }

    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--header-height);
      z-index: 100;
      transition: background 0.3s ease, box-shadow 0.3s ease;
      display: flex;
      align-items: center;
      backdrop-filter: blur(4px);
      background: transparent;
    }
    .site-header.scrolled {
      background: var(--primary-deep);
      box-shadow: 0 1px 0 var(--border-light);
      backdrop-filter: blur(20px);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 20px;
      height: 100%;
    }
    @media (min-width: 768px) {
      .header-inner { padding: 0 40px; }
    }
    @media (min-width: 1025px) {
      .header-inner { padding: 0 80px; }
    }
    .logo {
      font-size: 1.8rem;
      font-weight: 700;
      letter-spacing: 2px;
      color: white;
      display: flex;
      align-items: center;
      gap: 6px;
      white-space: nowrap;
    }
    .logo span {
      color: var(--accent-red);
      font-size: 2rem;
      margin-right: 4px;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }
    .nav-links a {
      color: rgba(255,255,255,0.9);
      font-weight: 500;
      font-size: 0.95rem;
      transition: color 0.2s;
      position: relative;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -6px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent-red);
      transition: width 0.3s ease;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--accent-red);
    }
    .nav-links a.active::after {
      width: 100%;
    }
    .header-btn {
      background: var(--accent-red);
      color: white;
      border: none;
      padding: 10px 24px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 0.9rem;
      transition: background 0.2s;
      white-space: nowrap;
    }
    .header-btn:hover {
      background: var(--accent-red-dark);
    }

    /* 汉堡菜单 */
    .menu-toggle {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
      z-index: 110;
    }
    .menu-toggle span {
      display: block;
      width: 26px;
      height: 2px;
      background: white;
      transition: 0.3s;
      border-radius: 2px;
    }
    .menu-toggle.open span:nth-child(1) {
      transform: rotate(45deg) translate(5px, 5px);
    }
    .menu-toggle.open span:nth-child(2) {
      opacity: 0;
    }
    .menu-toggle.open span:nth-child(3) {
      transform: rotate(-45deg) translate(5px, -5px);
    }

    @media (max-width: 767px) {
      .nav-links, .header-btn {
        display: none;
      }
      .menu-toggle {
        display: flex;
      }
      .mobile-menu {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: var(--primary-deep);
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 40px;
        opacity: 0;
        visibility: hidden;
        transform: translateY(-20px);
        transition: 0.35s ease;
        z-index: 105;
      }
      .mobile-menu.open {
        opacity: 1;
        visibility: visible;
        transform: translateY(0);
      }
      .mobile-menu a {
        font-size: 1.8rem;
        color: white;
        font-weight: 600;
      }
      .mobile-menu .header-btn {
        display: inline-block;
        margin-top: 20px;
      }
    }

    /* hero */
    .hero {
      height: 100vh;
      background: var(--primary-deep);
      display: flex;
      align-items: center;
      position: relative;
      overflow: hidden;
    }
    .hero-content {
      display: flex;
      align-items: center;
      width: 100%;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 20px;
      gap: 40px;
    }
    @media (min-width: 768px) {
      .hero-content { padding: 0 40px; }
    }
    @media (min-width: 1025px) {
      .hero-content { padding: 0 80px; }
    }
    .hero-left {
      flex: 0 0 55%;
      opacity: 0;
      transform: translateY(30px);
      animation: fadeUp 0.8s ease-out forwards;
    }
    .hero-right {
      flex: 0 0 45%;
      display: flex;
      justify-content: center;
      align-items: center;
      animation: float 6s ease-in-out infinite;
    }
    @keyframes fadeUp {
      to { opacity: 1; transform: translateY(0); }
    }
    @keyframes float {
      0%, 100% { transform: translateY(0); }
      50% { transform: translateY(-10px); }
    }
    .hero h1 {
      font-size: 3.8rem;
      font-weight: 700;
      color: white;
      line-height: 1.2;
      margin-bottom: 24px;
      letter-spacing: 1px;
    }
    .hero-sub {
      font-size: 1.1rem;
      color: rgba(241, 250, 238, 0.8);
      margin-bottom: 36px;
      max-width: 480px;
    }
    .hero-buttons {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }
    .hero-visual {
      width: 100%;
      height: 360px;
      background: radial-gradient(circle at 30% 30%, rgba(168, 218, 220, 0.2), transparent 70%);
      border-radius: 24px;
      display: flex;
      align-items: center;
      justify-content: center;
        position: relative;
    }
    .hero-visual::before {
      content: '';
      position: absolute;
      width: 80%;
      height: 80%;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      opacity: 0.85;
      border-radius: 24px;
      mask-image: radial-gradient(circle, black 40%, transparent 80%);
    }
    @media (max-width: 1024px) {
      .hero-content { flex-direction: column; text-align: center; }
      .hero-left, .hero-right { flex: auto; width: 100%; }
      .hero h1 { font-size: 2.6rem; }
      .hero-sub { margin-left: auto; margin-right: auto; }
    }

    /* 通用区块 */
    section {
      padding: 100px 0;
    }
    .section-title {
      font-size: 2.4rem;
      font-weight: 700;
      margin-bottom: 20px;
      color: var(--text-dark);
    }
    .dark-section {
      background: var(--primary-deep);
      color: white;
    }
    .dark-section .section-title {
      color: white;
    }

    /* 功能分组 interactive */
    .function-grid {
      display: flex;
      gap: 40px;
      align-items: flex-start;
    }
    .tabs-vertical {
      flex: 0 0 240px;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }
    .tab-btn {
      text-align: left;
      padding: 16px 20px;
      background: transparent;
      border: none;
      font-weight: 600;
      font-size: 1rem;
      color: var(--text-muted);
      position: relative;
      cursor: pointer;
      transition: color 0.2s;
      border-left: 3px solid transparent;
      background: #f8fafc;
      border-radius: 0 12px 12px 0;
    }
    .tab-btn.active {
      color: var(--accent-red);
      background: white;
      border-left-color: var(--accent-red);
      box-shadow: var(--shadow-sm);
    }
    .tab-content-panel {
      flex: 1;
      background: white;
      border-radius: var(--radius-md);
      padding: 32px;
      box-shadow: var(--shadow-sm);
      display: flex;
      gap: 30px;
      align-items: center;
    }
    .tab-text h3 { font-size: 1.6rem; margin-bottom: 16px; }
    .tab-text ul { list-style: none; margin-top: 20px; }
    .tab-text li { margin-bottom: 12px; display: flex; align-items: center; gap: 8px; }
    .tab-img {
      width: 240px;
      height: 180px;
      border-radius: 16px;
      background: #e5e7eb url('/assets/images/coverpic/cover-1.webp') center/cover no-repeat;
      flex-shrink: 0;
    }
    @media (max-width: 768px) {
      .function-grid { flex-direction: column; }
      .tabs-vertical { flex-direction: row; overflow-x: auto; flex: auto; gap: 12px; }
      .tab-btn { white-space: nowrap; border-left: none; border-bottom: 3px solid transparent; }
      .tab-content-panel { flex-direction: column; }
    }

    /* 场景卡片 */
    .scenario-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 30px;
    }
    .scenario-card {
      height: 400px;
      border-radius: 24px;
      position: relative;
      overflow: hidden;
      background: #1A1F2B;
      display: flex;
      align-items: flex-end;
      transition: transform 0.3s;
    }
    .scenario-card:hover {
      transform: translateY(-6px);
    }
    .scenario-card .bg-img {
      position: absolute;
      inset: 0;
      background-size: cover;
      background-position: center;
      transition: transform 0.5s;
    }
    .scenario-card:hover .bg-img {
      transform: scale(1.05);
    }
    .scenario-card .overlay {
      position: absolute;
      bottom: 0;
      width: 100%;
      padding: 40px;
      background: linear-gradient(transparent, rgba(11,15,25,0.9));
      color: white;
    }
    @media (max-width: 768px) {
      .scenario-grid { grid-template-columns: 1fr; }
    }

    /* 案例数字 */
    .stats-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 50px;
      align-items: center;
    }
    .big-numbers {
      display: flex;
      flex-wrap: wrap;
      gap: 40px;
    }
    .stat-item {
      font-size: 4rem;
      font-weight: 800;
      color: var(--accent-red);
      line-height: 1;
    }
    .case-cards {
      display: flex;
      gap: 24px;
      flex-wrap: wrap;
    }
    .case-card {
      background: white;
      border-radius: 20px;
      padding: 24px;
      box-shadow: var(--shadow-sm);
      flex: 1;
      min-width: 200px;
    }
    .case-img {
      height: 140px;
      background: #e5e7eb url('/assets/images/coverpic/cover-2.webp') center/cover no-repeat;
      border-radius: 12px;
      margin-bottom: 16px;
    }

    /* 价格 */
    .pricing-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 30px;
    }
    .pricing-card {
      background: white;
      border-radius: 24px;
      padding: 40px 28px;
      box-shadow: var(--shadow-sm);
      transition: 0.3s;
      border: 2px solid transparent;
      text-align: center;
    }
    .pricing-card.recommend {
      border-color: var(--accent-red);
      transform: scale(1.03);
      position: relative;
    }
    .badge {
      background: var(--accent-red);
      color: white;
      padding: 4px 16px;
      border-radius: 40px;
      font-size: 0.8rem;
      display: inline-block;
      margin-bottom: 16px;
    }
    @media (max-width: 768px) {
      .pricing-grid { grid-template-columns: 1fr; }
      .pricing-card.recommend { transform: none; }
    }

    /* faq */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      background: #F1FAEE;
      border-radius: 16px;
      margin-bottom: 16px;
      overflow: hidden;
    }
    .faq-question {
      padding: 20px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      background: white;
      padding: 0 20px;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding: 20px;
    }

    footer {
      background: var(--primary-deep);
      color: rgba(241,250,238,0.8);
      padding: 80px 0 40px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    @media (max-width: 768px) {
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }