/* roulang page: index */
:root {
      --primary: #E84A2D;
      --primary-hover: #C83A22;
      --secondary: #1A1A2E;
      --accent: #F5A623;
      --accent-light: #FFF3D6;
      --bg-light: #F9F9FB;
      --bg-dark: #1A1A2E;
      --bg-darker: #16213E;
      --text-main: #1A1A2E;
      --text-sub: #5A5A72;
      --text-white: #FFFFFF;
      --success: #2ECC71;
      --radius-xl: 24px;
      --radius-lg: 16px;
      --radius-md: 12px;
      --radius-sm: 8px;
      --shadow-card: 0 2px 12px rgba(26,26,46,0.04);
      --shadow-hover: 0 12px 32px rgba(26,26,46,0.1);
      --shadow-nav: 0 4px 20px rgba(0,0,0,0.06);
      --font-numbers: 'Inter', 'Roboto', 'Helvetica Neue', sans-serif;
      --font-cn: 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', sans-serif;
      --transition: all 0.25s ease;
      --container-max: 1280px;
      --header-height: 72px;
      --header-height-mobile: 60px;
    }

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

    html {
      scroll-behavior: smooth;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

    body {
      font-family: var(--font-cn);
      background-color: #FFFFFF;
      color: var(--text-main);
      line-height: 1.7;
      font-size: 1rem;
      font-weight: 400;
      overflow-x: hidden;
    }

    .container {
      max-width: var(--container-max);
      margin-left: auto;
      margin-right: auto;
      padding-left: 24px;
      padding-right: 24px;
      width: 100%;
    }

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

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      outline: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      transition: var(--transition);
      font-weight: 600;
      border-radius: var(--radius-md);
      white-space: nowrap;
    }

    h1, h2, h3, h4 {
      font-weight: 700;
      line-height: 1.25;
      color: var(--text-main);
    }

    h1 {
      font-size: clamp(2.2rem, 5vw, 3.5rem);
      font-weight: 800;
      letter-spacing: -0.02em;
    }

    h2 {
      font-size: clamp(1.8rem, 4vw, 2.5rem);
      margin-bottom: 1rem;
    }

    h3 {
      font-size: 1.35rem;
      font-weight: 600;
    }

    .section {
      padding: 80px 0;
    }

    @media (max-width: 768px) {
      .section {
        padding: 60px 0;
      }
      h2 {
        font-size: 1.8rem;
      }
    }

    /* ---------- 导航 ---------- */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      height: var(--header-height);
      background: rgba(255,255,255,0.8);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      transition: background 0.3s, box-shadow 0.3s;
      display: flex;
      align-items: center;
    }

    .header.scrolled {
      background: rgba(255,255,255,0.95);
      box-shadow: var(--shadow-nav);
    }

    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }

    .logo {
      font-size: 1.6rem;
      font-weight: 800;
      color: var(--secondary);
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .logo i {
      color: var(--primary);
      font-size: 2rem;
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 2rem;
    }

    .nav-links a {
      font-weight: 500;
      color: var(--text-main);
      position: relative;
      font-size: 0.95rem;
      padding: 6px 0;
    }

    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width 0.2s ease;
    }

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

    .nav-cta {
      background: var(--primary);
      color: white;
      padding: 10px 24px;
      border-radius: var(--radius-md);
      font-weight: 600;
    }

    .nav-cta:hover {
      background: var(--primary-hover);
      transform: translateY(-1px);
      box-shadow: 0 6px 16px rgba(232,74,45,0.3);
    }

    .burger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
      cursor: pointer;
    }

    .burger span {
      width: 26px;
      height: 2.5px;
      background: var(--secondary);
      border-radius: 3px;
      transition: var(--transition);
    }

    @media (max-width: 1024px) {
      .nav-links {
        gap: 1.2rem;
      }
    }

    @media (max-width: 768px) {
      .header {
        height: var(--header-height-mobile);
      }
      .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 80%;
        max-width: 360px;
        height: 100vh;
        background: rgba(26,26,46,0.95);
        backdrop-filter: blur(20px);
        flex-direction: column;
        justify-content: center;
        gap: 2.2rem;
        transition: right 0.35s ease;
      }
      .nav-links.active {
        right: 0;
      }
      .nav-links a {
        color: white;
        font-size: 1.3rem;
      }
      .nav-cta {
        background: var(--accent);
        color: var(--secondary);
      }
      .burger {
        display: flex;
      }
    }

    /* ---------- Hero ---------- */
    .hero {
      padding-top: calc(var(--header-height) + 40px);
      padding-bottom: 60px;
      background: var(--bg-light);
      position: relative;
      overflow: hidden;
    }

    .hero .container {
      display: flex;
      align-items: center;
      gap: 3rem;
    }

    .hero-left {
      flex: 0 0 55%;
    }

    .hero-right {
      flex: 1;
      position: relative;
    }

    .hero-right img {
      border-radius: var(--radius-xl);
      box-shadow: var(--shadow-hover);
      width: 100%;
      object-fit: cover;
    }

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

    .hero-sub {
      font-size: 1.2rem;
      color: var(--text-sub);
      margin: 1.2rem 0 2rem;
    }

    .hero-buttons {
      display: flex;
      gap: 1rem;
      flex-wrap: wrap;
      margin-bottom: 2.5rem;
    }

    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 14px 36px;
      font-weight: 700;
    }

    .btn-primary:hover {
      background: var(--primary-hover);
      transform: translateY(-2px);
      box-shadow: 0 10px 24px rgba(232,74,45,0.35);
    }

    .btn-outline {
      border: 2px solid var(--primary);
      color: var(--primary);
      background: transparent;
      padding: 14px 36px;
    }

    .btn-outline:hover {
      background: rgba(232,74,45,0.05);
    }

    .stats {
      display: flex;
      gap: 2rem;
      flex-wrap: wrap;
    }

    .stat-badge {
      background: white;
      padding: 0.6rem 1.4rem;
      border-radius: 30px;
      font-weight: 600;
      box-shadow: var(--shadow-card);
      display: flex;
      align-items: center;
      gap: 6px;
    }

    .stat-badge span {
      font-family: var(--font-numbers);
      color: var(--primary);
      font-weight: 700;
      font-size: 1.2rem;
    }

    .decor-circle {
      position: absolute;
      right: -80px;
      top: -60px;
      width: 380px;
      height: 380px;
      background: radial-gradient(circle, rgba(232,74,45,0.12) 0%, transparent 70%);
    }

    @media (max-width: 768px) {
      .hero .container {
        flex-direction: column;
      }
      .hero-left {
        flex: auto;
        text-align: center;
      }
      .hero-buttons, .stats {
        justify-content: center;
      }
    }

    /* ---------- 核心亮点 ---------- */
    .highlights {
      background: white;
    }

    .grid-highlights {
      display: grid;
      grid-template-columns: 1.5fr 1fr 1fr;
      grid-template-rows: auto auto;
      gap: 24px;
    }

    .card-highlight {
      background: white;
      border-radius: var(--radius-lg);
      padding: 32px;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
      display: flex;
      flex-direction: column;
    }

    .card-highlight:hover {
      transform: translateY(-8px);
      box-shadow: var(--shadow-hover);
    }

    .card-highlight.large {
      grid-row: span 2;
    }

    .highlight-icon {
      font-size: 2rem;
      color: var(--primary);
      margin-bottom: 1rem;
    }

    .highlight-number {
      font-family: var(--font-numbers);
      font-weight: 700;
      color: var(--accent);
      background: var(--accent-light);
      padding: 4px 12px;
      border-radius: 20px;
      align-self: flex-start;
      margin-top: auto;
      font-size: 0.9rem;
    }

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

    /* ---------- 案例瀑布流 ---------- */
    .cases {
      background: var(--bg-light);
    }

    .waterfall {
      columns: 3;
      column-gap: 24px;
    }

    .case-card {
      break-inside: avoid;
      background: white;
      border-radius: var(--radius-lg);
      overflow: hidden;
      margin-bottom: 24px;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }

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

    .case-img {
      overflow: hidden;
      height: 200px;
    }

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

    .case-card:hover .case-img img {
      transform: scale(1.04);
    }

    .case-tag {
      background: var(--accent);
      color: var(--secondary);
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 0.8rem;
      font-weight: 600;
      display: inline-block;
      margin: 16px 16px 0;
    }

    .case-content {
      padding: 8px 16px 20px;
    }

    @media (max-width: 1024px) {
      .waterfall {
        columns: 2;
      }
    }
    @media (max-width: 520px) {
      .waterfall {
        columns: 1;
      }
    }

    /* ---------- 方案对比 ---------- */
    .compare {
      background: var(--bg-dark);
      color: white;
    }

    .compare h2 {
      color: white;
    }

    .compare-grid {
      display: flex;
      gap: 24px;
      align-items: flex-start;
    }

    .compare-col {
      flex: 1;
      background: rgba(255,255,255,0.05);
      border-radius: var(--radius-lg);
      padding: 32px 24px;
    }

    .compare-col.featured {
      background: white;
      color: var(--text-main);
      transform: scale(1.04);
      box-shadow: 0 20px 40px rgba(0,0,0,0.4);
      position: relative;
    }

    .badge-recommend {
      background: var(--accent);
      color: var(--secondary);
      font-weight: 700;
      padding: 6px 18px;
      border-radius: 20px;
      position: absolute;
      top: -14px;
      right: 20px;
    }

    .compare-item {
      display: flex;
      justify-content: space-between;
      padding: 12px 0;
      border-bottom: 1px solid rgba(255,255,255,0.1);
    }

    .featured .compare-item {
      border-color: #eee;
    }

    @media (max-width: 768px) {
      .compare-grid {
        flex-direction: column;
      }
      .compare-col.featured {
        transform: none;
      }
    }

    /* ---------- FAQ ---------- */
    .faq {
      background: var(--bg-darker);
      color: white;
    }

    .faq h2 {
      color: white;
    }

    .accordion-item {
      border-bottom: 1px solid rgba(255,255,255,0.1);
    }

    .accordion-btn {
      width: 100%;
      background: none;
      color: white;
      font-size: 1.15rem;
      font-weight: 600;
      text-align: left;
      padding: 20px 8px;
      display: flex;
      justify-content: space-between;
    }

    .accordion-content {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: #ccc;
      padding-left: 8px;
    }

    .accordion-content.open {
      max-height: 200px;
      padding-bottom: 16px;
    }

    /* ---------- CTA ---------- */
    .cta-band {
      background: linear-gradient(135deg, var(--primary) 0%, #16213E 100%);
      text-align: center;
      color: white;
    }

    .cta-band h2 {
      color: white;
      font-size: 2.5rem;
    }

    .btn-accent {
      background: var(--accent);
      color: var(--secondary);
      padding: 16px 48px;
      font-weight: 700;
      font-size: 1.1rem;
    }

    .btn-accent:hover {
      filter: brightness(1.1);
    }

    /* ---------- 页脚 ---------- */
    .footer {
      background: var(--secondary);
      color: #ccc;
      padding: 60px 0 30px;
    }

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

    .footer a {
      color: #aaa;
    }

    .footer a:hover {
      color: white;
    }

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

    .social-icons i {
      font-size: 1.5rem;
      margin-right: 16px;
    }