/* roulang page: index */
:root {
      --primary-green: #0A8F3C;
      --primary-green-dark: #087A32;
      --accent-orange: #F15A24;
      --accent-neon: #C8E600;
      --dark-black: #1A1A1A;
      --deep-gray: #2A2A2A;
      --text-title: #1A1A1A;
      --text-body: #3D3D3D;
      --text-muted: #6B6B6B;
      --bg-warm: #F7F5F0;
      --bg-white: #FFFFFF;
      --border-light: #E5E1DA;
      --shadow-card: 0 2px 12px rgba(0,0,0,0.06);
      --shadow-card-hover: 0 8px 30px rgba(10,143,60,0.12);
      --shadow-nav: 0 1px 8px rgba(0,0,0,0.06);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-image: 20px;
      --font-heading: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --font-body: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --font-data: "DIN Alternate", "Arial Narrow", sans-serif;
      --spacing-section: 100px;
      --max-width: 1200px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
    }
    body {
      font-family: var(--font-body);
      font-size: 16px;
      line-height: 1.75;
      color: var(--text-body);
      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;
    }
    button, input, textarea {
      font-family: inherit;
    }
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: rgba(255,255,255,0.95);
      backdrop-filter: blur(10px);
      box-shadow: var(--shadow-nav);
      z-index: 1000;
      transition: background 0.3s ease;
      display: flex;
      align-items: center;
    }
    .header-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo {
      font-family: var(--font-heading);
      font-weight: 900;
      font-size: 26px;
      letter-spacing: 2px;
      color: var(--primary-green);
      display: flex;
      align-items: baseline;
    }
    .logo .accent {
      color: var(--accent-orange);
      font-size: 14px;
      margin-left: 6px;
      font-weight: 700;
    }
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }
    .nav-menu a {
      font-weight: 600;
      color: var(--text-title);
      transition: color 0.2s;
      font-size: 15px;
    }
    .nav-menu a:hover {
      color: var(--primary-green);
    }
    .nav-cta {
      background: var(--primary-green);
      color: white !important;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      transition: background 0.2s, transform 0.2s;
      display: inline-block;
    }
    .nav-cta:hover {
      background: var(--primary-green-dark);
      transform: translateY(-2px);
    }
    .burger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
      cursor: pointer;
      padding: 8px;
    }
    .burger span {
      width: 25px;
      height: 3px;
      background: var(--text-title);
      border-radius: 2px;
      transition: 0.3s;
    }
    @media (max-width: 767px) {
      .nav-menu {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: var(--bg-warm);
        flex-direction: column;
        justify-content: center;
        gap: 36px;
        transform: translateX(100%);
        transition: transform 0.4s ease;
        z-index: 999;
      }
      .nav-menu.active {
        transform: translateX(0);
      }
      .burger {
        display: flex;
        z-index: 1001;
      }
      .nav-cta {
        margin-top: 20px;
      }
    }
    /* Hero */
    #hero {
      padding-top: 120px;
      padding-bottom: 80px;
      background: var(--bg-white);
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-text {
      flex: 1;
    }
    .hero-badge {
      display: inline-block;
      background: var(--accent-orange);
      color: white;
      font-size: 13px;
      font-weight: 700;
      padding: 4px 16px;
      border-radius: 20px;
      margin-bottom: 20px;
      letter-spacing: 1px;
    }
    .hero-text h1 {
      font-family: var(--font-heading);
      font-weight: 900;
      font-size: 48px;
      line-height: 1.2;
      color: var(--text-title);
      margin-bottom: 18px;
    }
    .hero-sub {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 32px;
    }
    .hero-buttons {
      display: flex;
      gap: 18px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--primary-green);
      color: white;
      font-weight: 700;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      border: none;
      cursor: pointer;
      transition: 0.2s;
      display: inline-flex;
      align-items: center;
      gap: 8px;
      font-size: 16px;
    }
    .btn-primary:hover {
      background: var(--primary-green-dark);
      transform: translateY(-2px);
      box-shadow: 0 6px 18px rgba(10,143,60,0.3);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary-green);
      color: var(--primary-green);
      font-weight: 700;
      padding: 12px 30px;
      border-radius: var(--radius-btn);
      cursor: pointer;
      transition: 0.2s;
      display: inline-flex;
      align-items: center;
      gap: 8px;
      font-size: 16px;
    }
    .btn-outline:hover {
      background: rgba(10,143,60,0.08);
      transform: translateY(-2px);
    }
    .hero-image {
      flex: 1;
      position: relative;
    }
    .hero-image img {
      width: 100%;
      border-radius: var(--radius-image);
      box-shadow: 0 20px 40px rgba(0,0,0,0.2);
      transform: perspective(800px) rotateY(-2deg);
      transition: 0.3s;
      object-fit: cover;
      aspect-ratio: 4/3;
    }
    @media (max-width: 992px) {
      .hero-grid {
        flex-direction: column-reverse;
      }
      .hero-image img {
        transform: none;
      }
      .hero-text h1 {
        font-size: 38px;
      }
    }
    @media (max-width: 767px) {
      .hero-text h1 {
        font-size: 32px;
      }
      .hero-buttons .btn-primary, .hero-buttons .btn-outline {
        width: 100%;
        justify-content: center;
      }
    }
    /* 通用板块 */
    section {
      padding: var(--spacing-section) 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 48px;
    }
    .section-title h2 {
      font-family: var(--font-heading);
      font-weight: 700;
      font-size: 36px;
      color: var(--text-title);
    }
    .section-title p {
      color: var(--text-muted);
      margin-top: 12px;
    }
    /* 服务卡片 */
    #services {
      background: var(--bg-warm);
    }
    .cards-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
    }
    .service-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 32px 24px;
      box-shadow: var(--shadow-card);
      transition: 0.3s;
      text-align: center;
    }
    .service-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-card-hover);
    }
    .card-icon {
      width: 64px;
      height: 64px;
      background: rgba(10,143,60,0.1);
      border-radius: 50%;
      margin: 0 auto 20px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 28px;
      color: var(--primary-green);
      transition: 0.3s;
    }
    .service-card:hover .card-icon {
      background: var(--primary-green);
      color: white;
    }
    .service-card h3 {
      font-weight: 700;
      margin-bottom: 12px;
      font-size: 22px;
    }
    .service-card p {
      color: var(--text-muted);
      margin-bottom: 16px;
    }
    .card-link {
      color: var(--primary-green);
      font-weight: 700;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      transition: gap 0.2s;
    }
    .card-link:hover {
      gap: 12px;
    }
    @media (max-width: 992px) {
      .cards-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 767px) {
      .cards-grid {
        grid-template-columns: 1fr;
      }
    }
    /* 优势数据 */
    #advantages {
      background: var(--dark-black);
      color: white;
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 30px;
      text-align: center;
    }
    .stat-item .stat-number {
      font-family: var(--font-data);
      font-size: 48px;
      font-weight: 700;
      color: var(--accent-neon);
      display: block;
    }
    .stat-label {
      color: #ccc;
      margin-top: 8px;
    }
    @media (max-width: 992px) {
      .stats-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    /* 案例 */
    #cases .case-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }
    .case-card {
      position: relative;
      border-radius: 16px;
      overflow: hidden;
      aspect-ratio: 16/9;
    }
    .case-card img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      filter: grayscale(30%);
      transition: 0.3s;
    }
    .case-card:hover img {
      filter: grayscale(0);
      transform: scale(1.05);
    }
    .case-overlay {
      position: absolute;
      bottom: 0;
      left: 0;
      width: 100%;
      background: linear-gradient(transparent, rgba(0,0,0,0.7));
      color: white;
      padding: 16px;
      font-weight: 700;
    }
    @media (max-width: 768px) {
      #cases .case-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    /* 解决方案 */
    .solution-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
    }
    .solution-row.reverse {
      flex-direction: row-reverse;
    }
    .solution-img {
      flex: 1;
    }
    .solution-img img {
      border-radius: 16px;
      box-shadow: 0 12px 28px rgba(0,0,0,0.1);
      width: 100%;
    }
    .solution-text {
      flex: 1;
    }
    .solution-text h3 {
      font-size: 28px;
      margin-bottom: 16px;
    }
    .solution-list {
      list-style: none;
      margin: 20px 0;
    }
    .solution-list li {
      display: flex;
      align-items: center;
      gap: 10px;
      margin-bottom: 12px;
    }
    .solution-list li::before {
      content: "●";
      color: var(--primary-green);
      font-size: 18px;
    }
    @media (max-width: 992px) {
      .solution-row, .solution-row.reverse {
        flex-direction: column;
      }
    }
    /* FAQ */
    #faq {
      background: var(--bg-white);
    }
    .faq-container {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 20px 0;
    }
    .faq-question {
      font-weight: 700;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
      font-size: 18px;
      color: var(--text-title);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--text-body);
      padding-top: 0;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-top: 12px;
    }
    /* CTA */
    #cta {
      background: var(--deep-gray);
      color: white;
      text-align: center;
      padding: 80px 0;
    }
    #cta .btn-primary {
      background: var(--accent-orange);
      padding: 18px 48px;
      font-size: 18px;
      margin-top: 24px;
    }
    /* Footer */
    #footer {
      background: var(--deep-gray);
      color: #bbb;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    .footer-logo {
      font-weight: 900;
      font-size: 24px;
      color: white;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }
    .copyright {
      text-align: center;
      margin-top: 40px;
      color: #777;
    }