/* roulang page: index */
:root {
      --primary: #B87333;
      --primary-deep: #9A5F2A;
      --accent-gold: #D4A853;
      --dark-bg: #2C3E50;
      --body-bg: #FAF7F2;
      --card-bg: #FFFFFF;
      --light-section: #F5F0E8;
      --text-primary: #1E1E1E;
      --text-secondary: #6B6B6B;
      --text-muted: #4A4A4A;
      --border-light: #E8E2D8;
      --white: #FFFFFF;
      --shadow-card: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
      --shadow-card-hover: 0 8px 24px rgba(0,0,0,0.10), 0 2px 6px rgba(0,0,0,0.06);
      --shadow-header: 0 2px 12px rgba(0,0,0,0.04);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-container: 16px;
      --font-serif: "Noto Serif SC", "Source Han Serif SC", "SimSun", serif;
      --font-sans: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
      --font-number: "Inter", "Segoe UI", sans-serif;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--body-bg);
      color: var(--text-primary);
      line-height: 1.75;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.25s ease;
    }
    button, .btn {
      cursor: pointer;
      font-family: var(--font-sans);
      border: none;
      background: none;
      transition: all 0.25s ease;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 32px;
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 24px;
      }
    }
    @media (max-width: 520px) {
      .container {
        padding: 0 20px;
      }
    }

    /* header */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: var(--white);
      border-bottom: 1px solid var(--border-light);
      box-shadow: var(--shadow-header);
      height: 72px;
      display: flex;
      align-items: center;
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo-area {
      display: flex;
      align-items: center;
      gap: 10px;
      font-family: var(--font-serif);
      font-weight: 700;
      font-size: 1.35rem;
      color: var(--dark-bg);
      letter-spacing: 0.05em;
      white-space: nowrap;
    }
    .logo-icon {
      width: 32px;
      height: 32px;
      background: var(--primary);
      border-radius: 6px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-weight: 700;
      font-size: 1.2rem;
    }
    .main-nav {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .main-nav a {
      font-size: 1rem;
      font-weight: 500;
      color: var(--text-muted);
      padding: 8px 0;
      position: relative;
    }
    .main-nav a:hover,
    .main-nav a.active {
      color: var(--primary);
    }
    .main-nav a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width 0.3s ease;
    }
    .main-nav a:hover::after,
    .main-nav a.active::after {
      width: 100%;
    }
    .header-actions {
      display: flex;
      align-items: center;
      gap: 16px;
    }
    .search-box {
      display: flex;
      align-items: center;
      background: var(--light-section);
      border-radius: 20px;
      padding: 8px 16px;
      gap: 8px;
      color: var(--text-secondary);
    }
    .search-box input {
      border: none;
      background: transparent;
      outline: none;
      font-size: 0.9rem;
      width: 120px;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      border-radius: var(--radius-btn);
      padding: 10px 22px;
      font-weight: 600;
      font-size: 1rem;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      box-shadow: 0 2px 6px rgba(184,115,51,0.15);
    }
    .btn-primary:hover {
      background: var(--primary-deep);
      transform: translateY(-2px);
      box-shadow: 0 8px 18px rgba(184,115,51,0.25);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      border-radius: var(--radius-btn);
      padding: 10px 22px;
      font-weight: 600;
    }
    .btn-outline:hover {
      background: rgba(184,115,51,0.08);
      transform: translateY(-2px);
    }
    .btn-lg {
      padding: 16px 40px;
      font-size: 1.125rem;
      border-radius: 12px;
    }
    .hamburger {
      display: none;
      font-size: 1.6rem;
      color: var(--dark-bg);
    }
    @media (max-width: 1024px) {
      .main-nav, .header-actions .search-box {
        display: none;
      }
      .hamburger {
        display: block;
      }
    }

    /* hero */
    .hero-section {
      display: flex;
      align-items: center;
      min-height: 90vh;
      padding: 40px 0;
      background: var(--body-bg);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-content h1 {
      font-family: var(--font-serif);
      font-size: 3.5rem;
      font-weight: 800;
      line-height: 1.15;
      color: var(--dark-bg);
      margin-bottom: 1.5rem;
    }
    .hero-content .subtitle {
      font-size: 1.25rem;
      color: var(--text-secondary);
      line-height: 1.7;
      max-width: 480px;
      margin-bottom: 2rem;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
      margin-bottom: 1.5rem;
    }
    .trust-tag {
      display: flex;
      align-items: center;
      gap: 8px;
      color: var(--text-muted);
      font-size: 0.95rem;
    }
    .hero-image {
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: 20px;
      min-height: 420px;
      box-shadow: 0 12px 32px rgba(0,0,0,0.08);
    }
    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        gap: 32px;
      }
      .hero-image {
        order: -1;
        min-height: 280px;
      }
      .hero-content h1 {
        font-size: 2.2rem;
      }
      .hero-content .subtitle {
        font-size: 1.1rem;
      }
    }

    /* trust bar */
    .trust-bar {
      background: var(--light-section);
      padding: 28px 0;
    }
    .trust-logos {
      display: flex;
      justify-content: space-around;
      align-items: center;
      flex-wrap: wrap;
      gap: 32px;
      filter: grayscale(100%) opacity(0.75);
      transition: 0.3s;
    }
    .trust-logos:hover {
      filter: grayscale(0%) opacity(1);
    }
    .trust-logos i {
      font-size: 2rem;
      color: var(--text-muted);
    }
    @media (max-width: 640px) {
      .trust-logos {
        justify-content: center;
        gap: 24px;
      }
    }

    /* section titles */
    .section-title {
      font-family: var(--font-serif);
      font-size: 2.5rem;
      font-weight: 700;
      color: var(--dark-bg);
      margin-bottom: 0.75rem;
      position: relative;
      display: inline-block;
    }
    .section-title::before {
      content: '';
      width: 48px;
      height: 4px;
      background: var(--primary);
      display: block;
      margin-bottom: 12px;
      border-radius: 2px;
    }
    .section-sub {
      color: var(--text-secondary);
      font-size: 1.125rem;
      margin-bottom: 3rem;
    }

    /* highlights grid */
    .highlights-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
    }
    .highlight-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 32px 24px;
      text-align: center;
      box-shadow: var(--shadow-card);
      transition: all 0.3s ease;
    }
    .highlight-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }
    .highlight-icon {
      font-size: 2.2rem;
      color: var(--accent-gold);
      margin-bottom: 18px;
    }
    .highlight-card h3 {
      font-size: 1.35rem;
      font-weight: 600;
      margin-bottom: 12px;
    }
    @media (max-width: 1024px) {
      .highlights-grid { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 640px) {
      .highlights-grid { grid-template-columns: 1fr; }
    }

    /* case masonry */
    .case-grid {
      column-count: 3;
      column-gap: 24px;
    }
    .case-card {
      break-inside: avoid;
      margin-bottom: 24px;
      background: var(--card-bg);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: 0.35s ease;
    }
    .case-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }
    .case-img {
      width: 100%;
      display: block;
      object-fit: cover;
      transition: transform 0.35s ease;
    }
    .case-card:hover .case-img {
      transform: scale(1.03);
    }
    .case-body {
      padding: 20px;
    }
    .case-body h4 {
      font-weight: 600;
      font-size: 1.2rem;
      margin-bottom: 6px;
    }
    .case-tag {
      font-size: 0.8rem;
      background: var(--light-section);
      padding: 2px 10px;
      border-radius: 20px;
      color: var(--primary-deep);
    }
    @media (max-width: 1024px) {
      .case-grid { column-count: 2; }
    }
    @media (max-width: 640px) {
      .case-grid { column-count: 1; }
    }

    /* comparison table */
    .compare-table-wrapper {
      overflow-x: auto;
      border-radius: var(--radius-container);
    }
    .compare-table {
      width: 100%;
      border-collapse: collapse;
      background: white;
    }
    .compare-table th {
      background: var(--dark-bg);
      color: white;
      padding: 18px;
      font-weight: 600;
    }
    .compare-table td, .compare-table th {
      padding: 16px;
      border-bottom: 1px solid var(--border-light);
    }
    .compare-table tr:nth-child(even) {
      background: #FAF7F2;
    }
    .highlight-col {
      background: #FFF9F2;
      border-left: 3px solid var(--primary);
    }
    @media (max-width: 768px) {
      .compare-table-wrapper {
        display: none;
      }
      .accordion-compare {
        display: block;
      }
    }
    .accordion-compare {
      display: none;
    }
    .accordion-item {
      background: white;
      border-radius: var(--radius-card);
      margin-bottom: 16px;
      padding: 20px;
      box-shadow: var(--shadow-card);
    }

    /* faq */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }
    .faq-question {
      width: 100%;
      text-align: left;
      padding: 20px 0;
      font-weight: 600;
      font-size: 1.15rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
      color: var(--dark-bg);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--text-muted);
    }
    .faq-answer.open {
      max-height: 200px;
      padding-bottom: 16px;
    }

    /* cta banner */
    .cta-banner {
      background: var(--dark-bg);
      padding: 80px 0;
      text-align: center;
    }
    .cta-banner h2 {
      font-family: var(--font-serif);
      font-size: 2.5rem;
      color: white;
      margin-bottom: 1rem;
    }
    .btn-gold {
      background: var(--accent-gold);
      color: var(--dark-bg);
      font-weight: 700;
    }

    /* footer */
    .site-footer {
      background: var(--dark-bg);
      color: #C0C0C0;
      padding: 60px 0 20px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }
    .footer-col h4 {
      color: var(--accent-gold);
      margin-bottom: 16px;
      font-weight: 600;
    }
    @media (max-width: 768px) {
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }
    @media (max-width: 520px) {
      .footer-grid { grid-template-columns: 1fr; }
    }