/* roulang page: index */
:root {
      --primary: #D32F2F;
      --primary-hover: #B71C1C;
      --secondary: #FFB300;
      --secondary-hover: #FF8F00;
      --dark: #1A1A1A;
      --darker: #111111;
      --light-bg: #F5F5F5;
      --white: #FFFFFF;
      --text: #333333;
      --text-light: #666666;
      --border: #E0E0E0;
      --shadow-sm: 0 4px 12px rgba(0,0,0,0.06);
      --shadow: 0 4px 20px rgba(0,0,0,0.08);
      --shadow-hover: 0 12px 28px rgba(0,0,0,0.15);
      --radius: 12px;
      --radius-sm: 8px;
      --radius-pill: 40px;
      --transition: 0.25s ease;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
      --max-width: 1280px;
    }

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

    html {
      scroll-behavior: smooth;
      scroll-padding-top: 80px;
    }

    body {
      font-family: var(--font-sans);
      font-size: 16px;
      line-height: 1.75;
      color: var(--text);
      background-color: var(--white);
      -webkit-font-smoothing: antialiased;
    }

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

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      transition: var(--transition);
      border: none;
      outline: none;
    }

    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 32px;
    }

    /* 导航 */
    #nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      transition: all 0.3s ease;
      background: transparent;
      padding: 16px 0;
    }

    #nav.scrolled {
      background: var(--white);
      box-shadow: 0 4px 20px rgba(0,0,0,0.08);
      padding: 12px 0;
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 32px;
    }

    .logo {
      font-size: 1.6rem;
      font-weight: 800;
      letter-spacing: 1px;
      color: var(--white);
      display: flex;
      align-items: center;
      gap: 6px;
      transition: color 0.3s;
    }

    #nav.scrolled .logo {
      color: var(--dark);
    }

    .logo span {
      color: var(--secondary);
    }

    .nav-links {
      display: flex;
      gap: 36px;
      align-items: center;
    }

    .nav-links a {
      font-weight: 500;
      font-size: 1rem;
      color: rgba(255,255,255,0.9);
      position: relative;
      padding-bottom: 6px;
      transition: color 0.2s;
    }

    #nav.scrolled .nav-links a {
      color: var(--text);
    }

    .nav-links a:hover {
      color: var(--secondary);
    }

    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--secondary);
      transition: width 0.25s;
    }

    .nav-links a:hover::after {
      width: 100%;
    }

    .menu-toggle {
      display: none;
      flex-direction: column;
      gap: 6px;
      background: transparent;
      border: none;
      cursor: pointer;
    }

    .menu-toggle span {
      width: 28px;
      height: 2px;
      background: var(--white);
      transition: 0.3s;
    }

    #nav.scrolled .menu-toggle span {
      background: var(--dark);
    }

    /* 移动端菜单 */
    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 75%;
        max-width: 320px;
        height: 100vh;
        background: var(--dark);
        flex-direction: column;
        padding: 100px 32px 40px;
        gap: 28px;
        transition: right 0.35s ease;
        box-shadow: -8px 0 30px rgba(0,0,0,0.2);
      }
      .nav-links.active {
        right: 0;
      }
      .nav-links a {
        font-size: 1.3rem;
        color: white;
      }
      .menu-toggle {
        display: flex;
        z-index: 1001;
      }
      #nav.scrolled .nav-links a {
        color: white;
      }
    }

    /* Hero */
    #hero {
      background-color: var(--dark);
      color: white;
      min-height: 100vh;
      display: flex;
      align-items: center;
      padding-top: 80px;
    }

    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }

    .hero-content h1 {
      font-size: 3.2rem;
      font-weight: 800;
      line-height: 1.2;
      letter-spacing: 1px;
      margin-bottom: 24px;
    }

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

    .hero-sub {
      font-size: 1.2rem;
      opacity: 0.85;
      margin-bottom: 36px;
      max-width: 480px;
    }

    .btn-group {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }

    .btn-primary {
      background: var(--secondary);
      color: var(--dark);
      font-weight: 700;
      font-size: 1.1rem;
      padding: 14px 36px;
      border-radius: var(--radius-sm);
      letter-spacing: 0.5px;
    }

    .btn-primary:hover {
      background: var(--secondary-hover);
      transform: scale(1.04);
    }

    .btn-ghost {
      background: transparent;
      border: 2px solid white;
      color: white;
      font-weight: 600;
      padding: 12px 34px;
      border-radius: var(--radius-sm);
    }

    .btn-ghost:hover {
      background: white;
      color: var(--dark);
    }

    .hero-image img {
      border-radius: 24px;
      box-shadow: 0 20px 40px rgba(0,0,0,0.5);
    }

    /* 通用区块 */
    section {
      padding: 90px 0;
    }

    .section-title {
      text-align: center;
      font-size: 2.4rem;
      font-weight: 700;
      margin-bottom: 16px;
      letter-spacing: 0.5px;
    }

    .section-sub {
      text-align: center;
      color: var(--text-light);
      max-width: 640px;
      margin: 0 auto 56px;
    }

    /* 价值主张 */
    .value-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
    }

    .value-card {
      background: var(--white);
      padding: 32px 24px;
      border-bottom: 3px solid var(--primary);
      transition: 0.3s;
      border-radius: 0 0 8px 8px;
    }

    .value-card:hover {
      border-bottom-width: 6px;
      transform: translateY(-4px);
      box-shadow: var(--shadow);
    }

    .value-icon {
      width: 50px;
      height: 50px;
      background: var(--primary);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 1.6rem;
      margin-bottom: 20px;
    }

    /* 功能分组 */
    #features {
      background: var(--light-bg);
    }

    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }

    .feature-card {
      background: white;
      padding: 28px;
      border-radius: var(--radius);
      box-shadow: var(--shadow);
      display: flex;
      gap: 18px;
      transition: 0.3s;
    }

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

    .feature-icon {
      width: 48px;
      height: 48px;
      background: var(--primary);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 1.4rem;
      flex-shrink: 0;
    }

    /* 场景 */
    .scenario-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
      margin-bottom: 80px;
    }

    .scenario-row.reverse {
      direction: rtl;
    }

    .scenario-row.reverse .scenario-text {
      direction: ltr;
    }

    .scenario-img img {
      border-radius: 20px;
    }

    .tags {
      display: flex;
      gap: 12px;
      flex-wrap: wrap;
      margin-top: 18px;
    }

    .tag {
      background: var(--light-bg);
      padding: 6px 18px;
      border-radius: 30px;
      font-size: 0.9rem;
      font-weight: 500;
    }

    /* 案例 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }

    .case-card {
      background: white;
      border-radius: var(--radius);
      overflow: hidden;
      box-shadow: var(--shadow);
      transition: 0.3s;
    }

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

    .case-img {
      height: 200px;
      background-size: cover;
      background-position: center;
    }

    .case-body {
      padding: 22px;
    }

    .stat {
      color: var(--primary);
      font-weight: 800;
      font-size: 1.5rem;
    }

    /* 价格 */
    #pricing {
      background: var(--dark);
      color: white;
    }

    .pricing-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }

    .price-card {
      background: white;
      color: var(--text);
      border-radius: var(--radius);
      padding: 36px 28px;
      position: relative;
      box-shadow: var(--shadow);
      transition: 0.3s;
    }

    .price-card.featured {
      border-top: 5px solid var(--secondary);
    }

    .badge {
      position: absolute;
      top: 16px;
      right: 16px;
      background: var(--secondary);
      color: #111;
      font-weight: 700;
      padding: 4px 16px;
      border-radius: 20px;
      font-size: 0.8rem;
    }

    .price {
      font-size: 3rem;
      font-weight: 800;
      color: var(--primary);
      margin: 16px 0;
    }

    /* FAQ */
    .faq-list {
      max-width: 780px;
      margin: 0 auto;
    }

    .faq-item {
      border-bottom: 1px solid var(--border);
    }

    .faq-question {
      width: 100%;
      background: transparent;
      font-size: 1.15rem;
      font-weight: 600;
      padding: 20px 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      text-align: left;
      color: var(--text);
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-light);
    }

    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-bottom: 18px;
    }

    /* CTA 横幅 */
    #cta {
      background: var(--dark);
      text-align: center;
      padding: 80px 0;
    }

    /* 页脚 */
    #footer {
      background: var(--darker);
      color: #aaa;
      padding: 56px 0 28px;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 36px;
    }

    @media (max-width: 1024px) {
      .hero-grid, .scenario-row, .footer-grid {
        grid-template-columns: 1fr;
        text-align: center;
      }
      .value-grid, .features-grid, .cases-grid, .pricing-grid {
        grid-template-columns: 1fr 1fr;
      }
      .hero-content h1 {
        font-size: 2.5rem;
      }
      .nav-links {
        gap: 20px;
      }
    }

    @media (max-width: 640px) {
      .value-grid, .features-grid, .cases-grid, .pricing-grid {
        grid-template-columns: 1fr;
      }
      .btn-group {
        flex-direction: column;
        align-items: center;
      }
      .container {
        padding: 0 20px;
      }
      .hero-content h1 {
        font-size: 2rem;
      }
    }