/* roulang page: index */
:root {
      --primary: #2B3A42;
      --secondary: #C59B5F;
      --accent: #D46A4A;
      --bg-paper: #FAF7F2;
      --bg-card: #FFFFFF;
      --bg-dark: #1E2A30;
      --text-primary: #2B3A42;
      --text-secondary: #5F6B70;
      --text-on-dark: #F5F0E8;
      --text-muted-on-dark: #A0A8AC;
      --border: #E0D9CF;
      --shadow-card: 0 2px 8px rgba(43, 58, 66, 0.06), 0 1px 3px rgba(0,0,0,0.04);
      --shadow-hover: 0 6px 18px rgba(43, 58, 66, 0.1), 0 2px 6px rgba(0,0,0,0.05);
      --radius-sm: 6px;
      --radius-md: 8px;
      --radius-lg: 12px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Inter", system-ui, -apple-system, sans-serif;
      --transition: all 0.2s ease;
      --spacing-section: 100px;
      --container-max: 1200px;
      --header-height: 64px;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-paper);
      color: var(--text-primary);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

    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;
      background: none;
      transition: var(--transition);
    }

    h1, h2, h3, h4 {
      font-weight: 600;
      line-height: 1.3;
    }

    h1 {
      font-size: clamp(2.2rem, 5vw, 3rem);
      font-weight: 700;
      margin-bottom: 0.7em;
    }

    h2 {
      font-size: clamp(1.8rem, 4vw, 2.2rem);
      text-align: center;
      margin-bottom: 2.5rem;
      position: relative;
      padding-bottom: 0.5rem;
    }
    h2::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 50%;
      transform: translateX(-50%);
      width: 48px;
      height: 3px;
      background: var(--secondary);
      border-radius: 2px;
    }

    h3 {
      font-size: 1.25rem;
      font-weight: 600;
      margin-bottom: 0.5rem;
    }

    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 20px;
    }

    /* header / nav */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(250, 247, 242, 0.85);
      backdrop-filter: blur(8px);
      -webkit-backdrop-filter: blur(8px);
      border-bottom: 1px solid var(--border);
      height: var(--header-height);
      display: flex;
      align-items: center;
    }
    .header-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo {
      font-size: 1.5rem;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: 0.5px;
    }
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 2rem;
    }
    .nav-link {
      font-size: 0.95rem;
      color: var(--text-secondary);
      padding: 0.25rem 0;
      border-bottom: 2px solid transparent;
      font-weight: 500;
    }
    .nav-link:hover, .nav-link.active {
      color: var(--secondary);
      border-bottom-color: var(--secondary);
    }
    .btn-nav {
      background: var(--primary);
      color: var(--text-on-dark);
      padding: 0.5rem 1.2rem;
      border-radius: var(--radius-sm);
      font-weight: 500;
      font-size: 0.9rem;
      white-space: nowrap;
    }
    .btn-nav:hover {
      background: #1E2A30;
      transform: translateY(-1px);
    }
    .menu-toggle {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: transparent;
      border: none;
    }
    .menu-toggle span {
      width: 24px;
      height: 2px;
      background: var(--primary);
      border-radius: 2px;
    }

    /* hero */
    #hero {
      padding: 4rem 0 5rem;
      display: flex;
      align-items: center;
      min-height: 85vh;
    }
    .hero-grid {
      display: flex;
      gap: 3rem;
      align-items: center;
    }
    .hero-left {
      flex: 1 1 50%;
    }
    .hero-right {
      flex: 1 1 45%;
      position: relative;
      display: flex;
      justify-content: center;
      align-items: center;
    }
    .hero-visual {
      width: 100%;
      aspect-ratio: 4/3;
      background: linear-gradient(135deg, rgba(197,155,95,0.15) 0%, rgba(43,58,66,0.08) 100%);
      border-radius: var(--radius-lg);
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
      overflow: hidden;
      box-shadow: var(--shadow-card);
    }
    .hero-visual img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      border-radius: var(--radius-lg);
    }
    .hero-sub {
      font-size: 1.1rem;
      color: var(--text-secondary);
      margin-bottom: 2rem;
      line-height: 1.8;
      max-width: 90%;
    }
    .cta-group {
      display: flex;
      align-items: center;
      gap: 2rem;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--primary);
      color: var(--text-on-dark);
      padding: 0.85rem 2rem;
      border-radius: var(--radius-sm);
      font-weight: 500;
      display: inline-block;
      box-shadow: 0 2px 6px rgba(0,0,0,0.05);
    }
    .btn-primary:hover {
      background: #1E2A30;
      transform: translateY(-1px);
      box-shadow: var(--shadow-hover);
    }
    .btn-ghost {
      color: var(--secondary);
      font-weight: 500;
      border-bottom: 1px solid transparent;
    }
    .btn-ghost:hover {
      border-bottom-color: var(--secondary);
    }

    section {
      padding: var(--spacing-section) 0;
    }

    /* highlights */
    .highlights-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 2rem;
      margin-top: 2rem;
    }
    .highlight-card {
      background: var(--bg-card);
      padding: 2rem 1.8rem;
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      border: 1px solid var(--border);
      text-align: center;
      transition: var(--transition);
    }
    .highlight-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
      border-color: rgba(43,58,66,0.2);
    }
    .highlight-icon {
      width: 56px;
      height: 56px;
      background: rgba(197,155,95,0.12);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 1.2rem;
      font-size: 1.8rem;
      color: var(--secondary);
    }

    /* cases waterfall */
    .cases-masonry {
      columns: 2;
      column-gap: 24px;
      margin-top: 2rem;
    }
    .case-card {
      break-inside: avoid;
      background: var(--bg-card);
      border-radius: var(--radius-lg);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      margin-bottom: 24px;
      transition: var(--transition);
      border: 1px solid var(--border);
    }
    .case-card:hover {
      transform: translateY(-3px);
      box-shadow: var(--shadow-hover);
    }
    .case-img {
      width: 100%;
      aspect-ratio: 16/9;
      object-fit: cover;
      transition: transform 0.25s ease;
    }
    .case-card:hover .case-img {
      transform: scale(1.02);
    }
    .case-body {
      padding: 1.5rem;
    }
    .case-tag {
      background: rgba(197,155,95,0.12);
      color: var(--secondary);
      font-size: 0.8rem;
      padding: 0.2rem 0.7rem;
      border-radius: 20px;
      display: inline-block;
      margin-bottom: 0.6rem;
    }

    /* solutions */
    .solutions-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 1.8rem;
      margin-top: 2rem;
    }
    .solution-card {
      background: var(--bg-card);
      border-radius: var(--radius-md);
      padding: 2rem 1.8rem;
      border: 1px solid var(--border);
      box-shadow: var(--shadow-card);
      display: flex;
      flex-direction: column;
    }
    .solution-card.featured {
      border: 2px solid var(--secondary);
      background: rgba(197,155,95,0.03);
      position: relative;
    }
    .badge-recommend {
      position: absolute;
      top: -12px;
      right: 20px;
      background: var(--accent);
      color: white;
      font-size: 0.75rem;
      padding: 0.25rem 1rem;
      border-radius: 20px;
      font-weight: 600;
    }
    .solution-list {
      list-style: none;
      margin: 1.5rem 0 2rem;
      flex: 1;
    }
    .solution-list li {
      padding: 0.5rem 0;
      display: flex;
      align-items: center;
      gap: 0.5rem;
      color: var(--text-secondary);
    }
    .solution-list li::before {
      content: "✓";
      color: var(--secondary);
      font-weight: bold;
    }
    .btn-outline {
      border: 1px solid var(--primary);
      color: var(--primary);
      padding: 0.7rem 1.5rem;
      border-radius: var(--radius-sm);
      font-weight: 500;
      background: transparent;
    }
    .btn-outline:hover {
      background: var(--primary);
      color: white;
    }

    /* faq */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border);
    }
    .faq-question {
      width: 100%;
      text-align: left;
      padding: 1.2rem 0;
      font-size: 1.1rem;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      color: var(--primary);
      background: transparent;
    }
    .faq-question:hover {
      color: var(--secondary);
    }
    .faq-icon {
      font-size: 1.4rem;
      color: var(--secondary);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-secondary);
      padding: 0 0 0 0;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-bottom: 1.2rem;
    }

    /* contact */
    .contact-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 2.5rem;
      margin-top: 2rem;
    }
    .contact-form input, .contact-form textarea {
      width: 100%;
      padding: 0.9rem;
      border: 1px solid var(--border);
      border-radius: var(--radius-sm);
      background: white;
      margin-bottom: 1.2rem;
      font-family: inherit;
      transition: 0.2s;
    }
    .contact-form input:focus, .contact-form textarea:focus {
      border-color: var(--primary);
      outline: none;
    }
    .contact-info {
      display: flex;
      flex-direction: column;
      gap: 1.5rem;
      color: var(--text-secondary);
    }

    footer {
      background: var(--bg-dark);
      color: var(--text-on-dark);
      padding: 2.5rem 0;
    }
    .footer-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 1rem;
    }
    .footer-links a {
      color: var(--secondary);
      margin-left: 2rem;
    }

    @media (max-width: 1024px) {
      .highlights-grid { grid-template-columns: repeat(2, 1fr); }
      .solutions-grid { grid-template-columns: repeat(2, 1fr); }
      .cases-masonry { columns: 1; }
    }
    @media (max-width: 768px) {
      :root { --header-height: 56px; --spacing-section: 60px; }
      .nav-menu { display: none; position: absolute; top: var(--header-height); left: 0; width: 100%; background: var(--bg-paper); flex-direction: column; padding: 2rem; gap: 1.5rem; box-shadow: 0 6px 12px rgba(0,0,0,0.05); }
      .nav-menu.open { display: flex; }
      .menu-toggle { display: flex; }
      .hero-grid { flex-direction: column; }
      .highlights-grid { grid-template-columns: 1fr; }
      .solutions-grid { grid-template-columns: 1fr; }
      .contact-grid { grid-template-columns: 1fr; }
    }