/* roulang page: index */
:root {
      --deep-ink: #0B0C0E;
      --warm-cream: #F5F0E8;
      --terracotta: #E85D3F;
      --terracotta-deep: #C94A2F;
      --gray-body: #2A2D32;
      --gray-muted: #6F7378;
      --gray-border: #D1D0CC;
      --success-green: #1F7A5C;
      --white: #FFFFFF;
      --shadow-sm: 0px 4px 20px rgba(11, 12, 14, 0.04);
      --shadow-md: 0px 12px 32px rgba(11, 12, 14, 0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Noto Sans SC", sans-serif;
      --transition-smooth: 0.3s cubic-bezier(0.23, 1, 0.32, 1);
      --content-width: 1280px;
      --section-gap: 120px;
      --card-gap: 32px;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--warm-cream);
      color: var(--gray-body);
      line-height: 1.7;
      font-size: 17px;
      font-weight: 400;
      -webkit-font-smoothing: antialiased;
    }

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

    a {
      text-decoration: none;
      color: inherit;
    }

    button, input {
      font-family: inherit;
    }

    .container {
      max-width: var(--content-width);
      margin: 0 auto;
      padding: 0 24px;
    }

    /* Header & Navigation */
    #header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 100;
      background: rgba(11, 12, 14, 0.85);
      backdrop-filter: blur(8px);
      transition: background 0.3s ease;
      border-bottom: 1px solid rgba(245, 240, 232, 0.08);
    }
    #header.scrolled {
      background: #0B0C0E;
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
      padding: 0 24px;
      max-width: var(--content-width);
      margin: 0 auto;
    }
    .logo {
      font-size: 24px;
      font-weight: 700;
      letter-spacing: 2px;
      color: var(--warm-cream);
      white-space: nowrap;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      font-size: 15px;
      font-weight: 500;
      color: var(--gray-border);
      position: relative;
      padding-bottom: 4px;
      transition: color 0.2s;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--terracotta);
      transition: width 0.25s ease;
    }
    .nav-links a:hover {
      color: var(--terracotta);
    }
    .nav-links a:hover::after {
      width: 100%;
    }
    .nav-links a.active {
      color: var(--white);
    }
    .nav-links a.active::after {
      width: 100%;
      background: var(--terracotta);
    }
    .nav-cta {
      background: var(--terracotta);
      color: var(--white);
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-size: 14px;
      font-weight: 600;
      transition: background 0.25s, transform 0.25s;
      margin-left: 12px;
    }
    .nav-cta:hover {
      background: var(--terracotta-deep);
      transform: scale(1.03);
      color: white;
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 6px;
      cursor: pointer;
      background: transparent;
      border: none;
    }
    .hamburger span {
      width: 28px;
      height: 2px;
      background: var(--warm-cream);
      border-radius: 2px;
      transition: 0.3s;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 72px;
      left: 0;
      width: 100%;
      height: calc(100vh - 72px);
      background: #0B0C0E;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 36px;
      z-index: 99;
    }
    .mobile-menu.active {
      display: flex;
    }
    .mobile-menu a {
      color: var(--gray-border);
      font-size: 20px;
      font-weight: 500;
    }
    .mobile-menu .nav-cta {
      margin-left: 0;
    }

    /* Hero */
    #hero {
      height: 100vh;
      background: linear-gradient(rgba(11, 12, 14, 0.75), rgba(11, 12, 14, 0.8)), url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      display: flex;
      align-items: center;
      color: var(--white);
      position: relative;
    }
    .hero-content {
      max-width: 720px;
      opacity: 0;
      transform: translateY(20px);
      animation: fadeUp 0.8s forwards;
    }
    @keyframes fadeUp {
      to { opacity: 1; transform: translateY(0); }
    }
    .hero-content h1 {
      font-size: 56px;
      font-weight: 700;
      line-height: 1.2;
      letter-spacing: -0.5px;
      margin-bottom: 24px;
      color: var(--white);
    }
    .hero-content p {
      font-size: 18px;
      color: rgba(245, 240, 232, 0.8);
      max-width: 560px;
      margin-bottom: 40px;
    }
    .btn-group {
      display: flex;
      align-items: center;
      gap: 24px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--terracotta);
      color: var(--white);
      padding: 16px 40px;
      border-radius: var(--radius-btn);
      font-size: 16px;
      font-weight: 600;
      display: inline-block;
      transition: background 0.25s, transform 0.25s;
      border: none;
      cursor: pointer;
    }
    .btn-primary:hover {
      background: var(--terracotta-deep);
      transform: scale(1.03);
      color: white;
    }
    .btn-text {
      color: var(--white);
      font-weight: 500;
      border-bottom: 1px solid var(--terracotta);
      transition: color 0.2s, border-color 0.2s;
      padding-bottom: 4px;
    }
    .btn-text:hover {
      color: var(--terracotta);
      border-color: var(--terracotta);
    }

    /* Sections */
    section {
      padding: var(--section-gap) 0;
    }
    .section-title {
      font-size: 40px;
      font-weight: 600;
      color: var(--deep-ink);
      margin-bottom: 16px;
      position: relative;
      display: inline-block;
    }
    .section-title::after {
      content: '';
      display: block;
      width: 40px;
      height: 8px;
      background: var(--terracotta);
      margin-top: 8px;
    }
    .grid-4 {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: var(--card-gap);
      margin-top: 48px;
    }
    .metric-card {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-sm);
      text-align: center;
      transition: var(--transition-smooth);
    }
    .metric-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .metric-icon {
      width: 24px;
      height: 24px;
      margin: 0 auto 16px;
      background: var(--warm-cream);
      border-radius: 4px;
    }
    .metric-number {
      font-size: 48px;
      font-weight: 700;
      color: var(--deep-ink);
      font-variant-numeric: tabular-nums;
    }
    .metric-label {
      font-size: 14px;
      color: var(--gray-muted);
      margin-top: 8px;
    }

    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: var(--card-gap);
      margin-top: 48px;
    }
    .service-card {
      background: var(--white);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      overflow: hidden;
      transition: var(--transition-smooth);
      display: flex;
      flex-direction: column;
    }
    .service-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .service-img {
      height: 180px;
      background-size: cover;
      background-position: center;
    }
    .service-body {
      padding: 28px 32px 32px;
      display: flex;
      flex-direction: column;
      flex: 1;
    }
    .service-body h3 {
      font-size: 22px;
      font-weight: 600;
      color: var(--deep-ink);
      margin-bottom: 12px;
    }
    .service-body p {
      color: var(--gray-body);
      margin-bottom: 20px;
      flex: 1;
    }
    .service-link {
      color: var(--deep-ink);
      font-weight: 500;
      border-bottom: 1px solid var(--terracotta);
      align-self: flex-start;
      transition: 0.2s;
    }
    .service-link:hover {
      color: var(--terracotta);
    }

    .compare-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 32px;
      margin-top: 48px;
    }
    .compare-col {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-sm);
    }
    .compare-col.right {
      background: #F0F7F4;
      border: 1px solid rgba(31,122,92,0.15);
    }
    .compare-col h3 {
      font-size: 22px;
      font-weight: 600;
      margin-bottom: 24px;
      color: var(--deep-ink);
    }
    .compare-list {
      list-style: none;
    }
    .compare-list li {
      margin-bottom: 16px;
      display: flex;
      align-items: center;
      gap: 12px;
      font-size: 17px;
    }
    .left-bullet {
      width: 10px;
      height: 10px;
      background: var(--gray-border);
      border-radius: 50%;
    }
    .right-check {
      color: var(--success-green);
      font-weight: 600;
    }

    .faq-list {
      margin-top: 48px;
      max-width: 860px;
    }
    .faq-item {
      background: var(--white);
      border-radius: 8px;
      margin-bottom: 12px;
      border: 1px solid var(--gray-border);
      overflow: hidden;
      transition: border-color 0.2s;
    }
    .faq-item.active {
      border-color: var(--terracotta);
    }
    .faq-question {
      padding: 20px 24px;
      font-weight: 600;
      font-size: 18px;
      color: var(--deep-ink);
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      background: transparent;
      border: none;
      width: 100%;
      text-align: left;
    }
    .faq-icon {
      font-size: 24px;
      transition: transform 0.4s;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
    }
    .faq-answer-inner {
      padding: 0 24px 20px;
      color: var(--gray-body);
    }

    .contact-form {
      margin-top: 48px;
      display: flex;
      gap: 16px;
      max-width: 620px;
      flex-wrap: wrap;
    }
    .contact-input {
      flex: 1;
      padding: 14px 20px;
      border: 1px solid var(--gray-border);
      border-radius: var(--radius-btn);
      background: var(--white);
      font-size: 16px;
      outline: none;
      transition: 0.2s;
    }
    .contact-input:focus {
      border-color: var(--terracotta);
      box-shadow: 0 0 0 3px rgba(232,93,63,0.15);
    }
    .privacy-note {
      font-size: 13px;
      color: var(--gray-muted);
      margin-top: 16px;
    }

    footer {
      background: var(--deep-ink);
      color: var(--gray-muted);
      padding: 60px 0 40px;
    }
    .footer-grid {
      display: flex;
      justify-content: space-between;
      align-items: flex-start;
      flex-wrap: wrap;
      gap: 40px;
    }
    .footer-logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--warm-cream);
      letter-spacing: 2px;
    }
    .footer-desc {
      max-width: 260px;
      margin-top: 12px;
      font-size: 15px;
    }
    .footer-links a {
      color: var(--gray-muted);
      margin-right: 24px;
      font-size: 15px;
      border-bottom: 1px solid transparent;
    }
    .footer-links a:hover {
      color: var(--terracotta);
      border-color: var(--terracotta);
    }
    .copyright {
      margin-top: 40px;
      font-size: 14px;
      border-top: 1px solid rgba(255,255,255,0.1);
      padding-top: 24px;
      text-align: center;
    }

    @media (max-width: 1024px) {
      .grid-4 { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 768px) {
      :root { --section-gap: 80px; }
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .hero-content h1 { font-size: 38px; }
      .section-title { font-size: 30px; }
      .grid-3 { grid-template-columns: 1fr; }
      .compare-grid { grid-template-columns: 1fr; }
      .metric-number { font-size: 36px; }
      .card, .metric-card, .service-body { padding: 24px; }
      .contact-form { flex-direction: column; }
      .btn-primary { width: 100%; text-align: center; }
    }
    @media (max-width: 520px) {
      .hero-content h1 { font-size: 32px; }
      .grid-4 { grid-template-columns: 1fr; }
      .btn-group { flex-direction: column; align-items: flex-start; }
    }