/* roulang page: index */
:root {
      --primary: #0A2E5C;
      --primary-light: #1A4A7A;
      --accent: #F5A623;
      --accent-dark: #E09515;
      --bg: #F9FAFB;
      --card-bg: #FFFFFF;
      --text: #1F2937;
      --text-weak: #6B7280;
      --border: #E5E7EB;
      --border-light: #F3F4F6;
      --shadow-sm: 0 4px 12px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(10,46,92,0.12);
      --shadow-lg: 0 16px 32px rgba(10,46,92,0.08);
      --radius-card: 16px;
      --radius-btn: 8px;
      --radius-img: 24px;
      --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --gap: 24px;
      --max-width: 1200px;
    }

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

    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }

    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s;
    }

    img {
      max-width: 100%;
      height: auto;
      display: block;
      border-radius: var(--radius-card);
    }

    button, input, textarea {
      font-family: inherit;
    }

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

    /* ---------- TOP BAR ---------- */
    .top-bar {
      background: var(--primary);
      color: rgba(255,255,255,0.9);
      font-size: 0.8rem;
      height: 36px;
      display: flex;
      align-items: center;
    }
    .top-bar .container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .top-bar a {
      color: white;
      font-weight: 500;
      margin-left: 20px;
      transition: color 0.2s;
    }
    .top-bar a:hover {
      color: var(--accent);
    }

    /* ---------- MAIN NAV ---------- */
    .main-nav {
      background: white;
      height: 64px;
      border-bottom: 1px solid var(--border);
      position: sticky;
      top: 0;
      z-index: 50;
      display: flex;
      align-items: center;
    }
    .main-nav .container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo-area {
      display: flex;
      align-items: center;
      gap: 8px;
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--primary);
    }
    .logo-icon {
      font-size: 1.8rem;
      color: var(--accent);
    }
    .nav-links {
      display: flex;
      gap: 32px;
      font-size: 1rem;
      font-weight: 500;
      color: var(--text);
    }
    .nav-links a {
      padding: 4px 0;
      border-bottom: 3px solid transparent;
      transition: border-color 0.2s, color 0.2s;
    }
    .nav-links a:hover,
    .nav-links a.active {
      border-bottom-color: var(--accent);
      color: var(--primary);
    }

    /* hamburger */
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
      cursor: pointer;
      padding: 8px;
    }
    .hamburger span {
      display: block;
      width: 24px;
      height: 2px;
      background: var(--primary);
      border-radius: 2px;
    }
    .mobile-menu {
      display: none;
      position: absolute;
      top: 64px;
      left: 0;
      width: 100%;
      background: white;
      flex-direction: column;
      padding: 20px;
      border-bottom: 1px solid var(--border);
      box-shadow: var(--shadow-md);
      z-index: 40;
    }
    .mobile-menu a {
      padding: 12px 0;
      border-bottom: 1px solid var(--border-light);
      font-weight: 500;
    }
    .mobile-menu.show {
      display: flex;
    }

    /* ---------- HERO ---------- */
    .hero {
      padding: 80px 0;
      background: linear-gradient(180deg, #F2F5F9 0%, #F9FAFB 100%);
    }
    .hero .container {
      display: flex;
      align-items: center;
      gap: 48px;
    }
    .hero-left {
      flex: 0 0 60%;
    }
    .hero-left h1 {
      font-size: 2.8rem;
      font-weight: 700;
      color: var(--primary);
      line-height: 1.3;
      margin-bottom: 0.8em;
    }
    .hero-left .subtitle {
      font-size: 1.2rem;
      color: var(--text-weak);
      margin-bottom: 2em;
      max-width: 480px;
    }
    .badge-row {
      display: flex;
      gap: 20px;
      margin-bottom: 2em;
    }
    .stat-badge {
      background: rgba(245,166,35,0.08);
      border-radius: 12px;
      padding: 12px 20px;
      color: var(--primary);
      font-weight: 700;
      font-size: 1.3rem;
      border: 1px solid rgba(245,166,35,0.2);
    }
    .stat-badge span {
      font-size: 0.8rem;
      display: block;
      font-weight: 400;
      color: var(--text-weak);
    }
    .btn-primary {
      background: var(--accent);
      color: white;
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      border: none;
      cursor: pointer;
      font-size: 1rem;
      transition: background 0.3s, box-shadow 0.3s;
      display: inline-block;
    }
    .btn-primary:hover {
      background: var(--accent-dark);
      box-shadow: 0 8px 16px rgba(245,166,35,0.3);
    }
    .btn-outline {
      background: transparent;
      color: var(--primary);
      border: 1px solid var(--primary);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 1rem;
      transition: all 0.3s;
      display: inline-block;
      margin-left: 12px;
    }
    .btn-outline:hover {
      background: var(--primary);
      color: white;
    }
    .hero-right {
      flex: 0 0 40%;
      position: relative;
    }
    .hero-img-card {
      background: #E5E7EB;
      border-radius: var(--radius-img);
      overflow: hidden;
      box-shadow: var(--shadow-md);
    }
    .hero-img-card img {
      width: 100%;
      object-fit: cover;
      aspect-ratio: 4/3;
    }
    .hero-overlay-card {
      position: absolute;
      bottom: -10px;
      left: 20px;
      right: 20px;
      background: rgba(255,255,255,0.75);
      backdrop-filter: blur(12px);
      border-radius: 16px;
      padding: 16px;
      font-weight: 500;
      color: var(--primary);
      box-shadow: var(--shadow-sm);
      border: 1px solid rgba(255,255,255,0.8);
    }

    /* ---------- SECTION COMMON ---------- */
    section {
      padding: 80px 0;
    }
    .section-title {
      font-size: 2rem;
      font-weight: 700;
      color: var(--primary);
      margin-bottom: 0.5em;
    }
    .section-sub {
      color: var(--text-weak);
      font-size: 1.1rem;
      margin-bottom: 3em;
    }
    .text-center {
      text-align: center;
    }

    /* ---------- HIGHLIGHTS GRID ---------- */
    .highlights-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: var(--gap);
    }
    .highlight-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 32px 24px;
      box-shadow: var(--shadow-sm);
      border: 1px solid var(--border);
      transition: all 0.3s ease;
    }
    .highlight-card:hover {
      box-shadow: var(--shadow-md);
      border-color: var(--primary);
      transform: translateY(-4px);
    }
    .highlight-number {
      font-size: 2.8rem;
      font-weight: 700;
      color: var(--accent);
      margin-bottom: 12px;
    }
    .highlight-card h3 {
      font-size: 1.5rem;
      font-weight: 600;
      margin-bottom: 12px;
    }

    /* ---------- CASE WATERFALL ---------- */
    .case-grid {
      columns: 3;
      column-gap: 24px;
    }
    .case-card {
      background: white;
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      border: 1px solid var(--border);
      break-inside: avoid;
      margin-bottom: 24px;
      transition: all 0.3s;
    }
    .case-card:hover {
      box-shadow: var(--shadow-md);
      transform: scale(1.01);
    }
    .case-img {
      background: #E5E7EB;
      aspect-ratio: 16/10;
      overflow: hidden;
    }
    .case-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: transform 0.3s;
    }
    .case-card:hover .case-img img {
      transform: scale(1.04);
    }
    .case-info {
      padding: 20px;
      border-top: 1px solid var(--border-light);
    }
    .case-tag {
      color: var(--accent);
      font-weight: 600;
      font-size: 0.8rem;
      margin-bottom: 6px;
    }
    .case-stat {
      font-weight: 700;
      color: var(--primary);
    }

    /* ---------- COMPARE ---------- */
    .compare-row {
      display: flex;
      gap: 32px;
    }
    .compare-col {
      flex: 1;
      background: white;
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-sm);
    }
    .compare-col.highlight {
      background: linear-gradient(135deg, #F0F4FA 0%, white 100%);
      border: 1px solid var(--primary);
    }
    .compare-item {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-bottom: 16px;
    }
    .strikethrough {
      text-decoration: line-through;
      color: var(--text-weak);
    }
    .check-icon {
      color: var(--accent);
      font-weight: bold;
    }

    /* ---------- CTA BANNER ---------- */
    .cta-banner {
      background: linear-gradient(135deg, #0A2E5C 0%, #1A4A7A 100%);
      padding: 80px 0;
      text-align: center;
      color: white;
    }
    .cta-banner h2 {
      font-size: 2.2rem;
    }
    .cta-small {
      margin-top: 12px;
      opacity: 0.8;
    }

    /* ---------- FAQ ---------- */
    .faq-item {
      border-bottom: 1px solid var(--border);
      padding: 16px 0;
    }
    .faq-question {
      font-weight: 600;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      transition: background 0.2s;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      padding-left: 20px;
      color: var(--text-weak);
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      margin-top: 12px;
    }

    /* ---------- FOOTER ---------- */
    .footer {
      background: var(--primary);
      color: rgba(255,255,255,0.8);
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }
    .footer a {
      color: rgba(255,255,255,0.7);
    }
    .footer a:hover {
      color: var(--accent);
    }
    .copyright {
      border-top: 1px solid rgba(255,255,255,0.15);
      margin-top: 40px;
      padding-top: 20px;
      display: flex;
      justify-content: space-between;
      font-size: 0.85rem;
    }

    /* ---------- RESPONSIVE ---------- */
    @media (max-width: 1024px) {
      .hero .container { flex-direction: column; }
      .hero-left, .hero-right { flex: auto; width: 100%; }
      .case-grid { columns: 2; }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .hero-left h1 { font-size: 2rem; }
      .highlights-grid { grid-template-columns: 1fr 1fr; }
      .compare-row { flex-direction: column; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      .case-grid { columns: 1; }
      .badge-row { flex-wrap: wrap; }
    }
    @media (max-width: 520px) {
      .highlights-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr; }
    }