/* roulang page: index */
/* ----- 设计变量 ----- */
    :root {
      --primary: #F04E23;
      --primary-hover: #D43D1A;
      --primary-soft: rgba(240, 78, 35, 0.08);
      --secondary: #1A1A1A;
      --accent: #7B2FBE;
      --bg-warm: #FAF8F6;
      --white: #FFFFFF;
      --text-main: #1A1A1A;
      --text-secondary: #4A4A4A;
      --text-muted: #6B6B6B;
      --border-light: rgba(0,0,0,0.06);
      --shadow-card: 0 2px 8px rgba(0,0,0,0.04);
      --shadow-card-hover: 0 8px 32px rgba(240,78,35,0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-tag: 6px;
      --font-title: 'Inter', 'PingFang SC', 'Noto Sans SC', system-ui, sans-serif;
      --font-body: 'PingFang SC', 'Noto Sans SC', 'Inter', system-ui, sans-serif;
      --font-number: 'DIN Alternate', 'Inter', 'PingFang SC', system-ui, sans-serif;
      --transition: 0.25s ease;
      --container-max: 1280px;
      --section-gap: 80px;
    }

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

    body {
      font-family: var(--font-body);
      font-size: 16px;
      line-height: 1.75;
      color: var(--text-main);
      background-color: var(--bg-warm);
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

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

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
    }

    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }

    @media (max-width: 768px) {
      .container {
        padding: 0 16px;
      }
      :root {
        --section-gap: 60px;
      }
    }

    /* 工具类 */
    .section {
      padding: var(--section-gap) 0;
    }

    .section-title {
      font-family: var(--font-title);
      font-size: 2.2rem;
      font-weight: 700;
      letter-spacing: -0.02em;
      color: var(--secondary);
      margin-bottom: 16px;
      line-height: 1.3;
    }

    .section-desc {
      color: var(--text-secondary);
      max-width: 700px;
      margin-bottom: 40px;
      font-size: 1.1rem;
    }

    /* ----- 顶部信息条 ----- */
    .top-bar {
      background: var(--secondary);
      height: 36px;
      display: flex;
      align-items: center;
      font-size: 12px;
      color: rgba(255,255,255,0.7);
    }
    .top-bar .container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .top-bar-left {
      display: flex;
      align-items: center;
      gap: 12px;
    }
    .domain-tag {
      color: rgba(255,255,255,0.6);
    }
    .separator {
      width: 1px;
      height: 14px;
      background: rgba(255,255,255,0.2);
    }
    .top-bar-right {
      display: flex;
      align-items: center;
      gap: 16px;
    }
    .hotline {
      display: flex;
      align-items: center;
      gap: 6px;
    }

    /* ----- 主导航 ----- */
    .main-header {
      background: var(--bg-warm);
      height: 72px;
      border-bottom: 1px solid var(--border-light);
      position: sticky;
      top: 0;
      z-index: 50;
      backdrop-filter: blur(8px);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
    }
    .logo {
      font-family: var(--font-title);
      font-weight: 800;
      font-size: 24px;
      color: var(--primary);
      display: flex;
      align-items: center;
      gap: 4px;
    }
    .logo i {
      font-size: 18px;
      color: var(--accent);
    }
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-link {
      font-weight: 500;
      color: var(--text-main);
      position: relative;
      padding: 8px 0;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width 0.25s ease;
    }
    .nav-link:hover {
      color: var(--primary);
    }
    .nav-link:hover::after {
      width: 100%;
    }
    .btn-primary-sm {
      background: var(--primary);
      color: white;
      padding: 10px 22px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 14px;
      white-space: nowrap;
    }
    .btn-primary-sm:hover {
      background: var(--primary-hover);
      box-shadow: 0 0 0 2px rgba(240,78,35,0.3);
    }

    .hamburger {
      display: none;
      font-size: 24px;
      background: none;
      border: none;
      color: var(--secondary);
    }

    /* 移动端导航 */
    @media (max-width: 768px) {
      .nav-menu {
        display: none;
        position: absolute;
        top: 72px;
        left: 0;
        width: 100%;
        background: var(--white);
        flex-direction: column;
        padding: 24px;
        box-shadow: var(--shadow-card);
        gap: 16px;
        align-items: flex-start;
      }
      .nav-menu.active {
        display: flex;
      }
      .hamburger {
        display: block;
      }
    }

    /* ----- 首屏 Hero 双栏 ----- */
    .hero {
      background: var(--bg-warm);
      position: relative;
      overflow: hidden;
    }
    .hero .container {
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-left {
      flex: 0 0 60%;
    }
    .hero-right {
      flex: 0 0 40%;
      position: relative;
    }
    .hero h1 {
      font-family: var(--font-title);
      font-weight: 800;
      font-size: 3.2rem;
      line-height: 1.2;
      letter-spacing: -0.02em;
      color: var(--secondary);
      margin-bottom: 20px;
    }
    .hero-sub {
      font-size: 1.3rem;
      font-weight: 600;
      color: var(--primary);
      margin-bottom: 16px;
    }
    .hero-desc {
      color: var(--text-secondary);
      margin-bottom: 32px;
      max-width: 480px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
      margin-bottom: 32px;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      border: none;
      transition: 0.25s ease;
      display: inline-block;
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      box-shadow: 0 0 0 2px rgba(240,78,35,0.4);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
    }
    .btn-outline:hover {
      background: rgba(240,78,35,0.1);
    }
    .trust-badges {
      display: flex;
      gap: 24px;
      color: var(--text-muted);
      font-weight: 500;
    }
    .hero-image {
      border-radius: 16px;
      overflow: hidden;
      box-shadow: 0 20px 40px rgba(0,0,0,0.08);
      background: #ddd;
    }
    .floating-card {
      position: absolute;
      bottom: -20px;
      right: -20px;
      background: var(--accent);
      color: white;
      padding: 16px 24px;
      border-radius: var(--radius-card);
      font-weight: 700;
      font-family: var(--font-number);
      font-size: 1.6rem;
      box-shadow: 0 12px 24px rgba(123,47,190,0.3);
    }
    @media (max-width: 768px) {
      .hero .container {
        flex-direction: column;
      }
      .hero-left, .hero-right {
        flex: 1 1 auto;
        width: 100%;
      }
      .hero h1 {
        font-size: 2.4rem;
      }
    }

    /* 核心亮点网格 2x3 */
    .highlights-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .highlight-card {
      background: var(--white);
      padding: 32px 24px;
      border-radius: var(--radius-card);
      border: 1px solid var(--border-light);
      box-shadow: var(--shadow-card);
      transition: all 0.3s ease;
      position: relative;
    }
    .highlight-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
      border-left: 3px solid var(--primary);
    }
    .highlight-icon {
      font-size: 28px;
      color: var(--primary);
      margin-bottom: 16px;
    }
    .highlight-card h3 {
      font-family: var(--font-title);
      font-weight: 700;
      margin-bottom: 8px;
    }
    @media (max-width: 1024px) {
      .highlights-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 520px) {
      .highlights-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 案例瀑布流 */
    .case-waterfall {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .case-card {
      background: var(--white);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: 0.3s;
    }
    .case-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }
    .case-img {
      height: 200px;
      background-size: cover;
      background-position: center;
      transition: transform 0.3s;
    }
    .case-card:hover .case-img {
      transform: scale(1.03);
    }
    .case-content {
      padding: 20px;
    }
    .case-tag {
      background: var(--primary-soft);
      color: var(--primary);
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 12px;
      font-weight: 600;
    }
    @media (max-width: 768px) {
      .case-waterfall {
        grid-template-columns: repeat(2, 1fr);
      }
    }

    /* 方案对比 */
    .compare-dual {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 32px;
    }
    .compare-col {
      background: white;
      padding: 32px;
      border-radius: var(--radius-card);
      border: 1px solid var(--border-light);
    }
    .compare-col.recommended {
      border: 2px solid var(--accent);
      position: relative;
    }
    .badge-recommend {
      position: absolute;
      top: -12px;
      right: 20px;
      background: var(--accent);
      color: white;
      padding: 4px 16px;
      border-radius: 20px;
      font-size: 13px;
      font-weight: 600;
    }
    .compare-item {
      display: flex;
      align-items: center;
      gap: 10px;
      margin: 12px 0;
    }
    .icon-check { color: var(--primary); }
    .icon-cross { color: #ccc; }

    /* 数据带 */
    .data-strip {
      background: #F2EFEC;
      display: flex;
      justify-content: space-around;
      text-align: center;
      flex-wrap: wrap;
    }
    .data-number {
      font-family: var(--font-number);
      font-size: 2.8rem;
      font-weight: 700;
      color: var(--primary);
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 20px 0;
    }
    .faq-question {
      font-weight: 600;
      font-size: 18px;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: 0.4s;
      color: var(--text-secondary);
      background: #f9f9f9;
      padding: 0 16px;
      margin-top: 8px;
      border-radius: 8px;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding: 16px;
    }

    /* CTA 横幅 */
    .cta-banner {
      background: linear-gradient(105deg, #F04E23 0%, #7B2FBE 100%);
      color: white;
      text-align: center;
      padding: 80px 0;
    }
    .btn-white-outline {
      border: 1.5px solid white;
      color: white;
      padding: 14px 32px;
      border-radius: 8px;
      font-weight: 600;
      background: transparent;
    }

    /* 页脚 */
    .footer {
      background: var(--secondary);
      color: rgba(255,255,255,0.7);
      padding: 60px 0 20px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 1.5fr 1fr 1fr 1fr;
      gap: 32px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 动画 */
    .fade-up {
      opacity: 0;
      transform: translateY(24px);
      transition: 0.6s ease;
    }
    .fade-up.visible {
      opacity: 1;
      transform: translateY(0);
    }