/* roulang page: index */
:root {
      --flame-orange: #F04E23;
      --deep-charcoal: #1E1E1E;
      --bright-yellow: #FFB81C;
      --warm-light-gray: #F5F5F0;
      --dark-moss-green: #0B3B2F;
      --card-bg: #FFFFFF;
      --body-bg: #F5F5F0;
      --text-primary: #1E1E1E;
      --text-secondary: #555555;
      --text-muted: #777777;
      --link-hover-underline: #FFB81C;
      --card-shadow: 0 4px 20px rgba(0, 0, 0, 0.06);
      --card-shadow-hover: 0 16px 32px rgba(0, 0, 0, 0.10);
      --border-radius-card: 16px;
      --border-radius-btn: 12px;
      --spacing-xs: 0.5rem;
      --spacing-sm: 1rem;
      --spacing-md: 2rem;
      --spacing-lg: 3rem;
      --spacing-xl: 5rem;
      --max-width: 1280px;
      --header-height: 68px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
      scroll-padding-top: var(--header-height);
      font-size: 16px;
    }
    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", "Inter", "DIN Alternate", sans-serif;
      background-color: var(--body-bg);
      color: var(--text-primary);
      line-height: 1.8;
      font-weight: 400;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: var(--max-width);
      margin-left: auto;
      margin-right: auto;
      padding-left: 2rem;
      padding-right: 2rem;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s, background-color 0.2s;
    }
    img {
      display: block;
      max-width: 100%;
      height: auto;
    }
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 0.75rem 1.8rem;
      border-radius: var(--border-radius-btn);
      font-weight: 700;
      font-size: 1rem;
      letter-spacing: 0.02em;
      border: none;
      cursor: pointer;
      transition: all 0.25s ease;
      line-height: 1.4;
      text-align: center;
    }
    .btn-primary {
      background-color: var(--flame-orange);
      color: #FFFFFF;
      box-shadow: 0 6px 16px rgba(240, 78, 35, 0.3);
    }
    .btn-primary:hover {
      background-color: #C93D1A;
      transform: translateY(-2px);
      box-shadow: 0 12px 24px rgba(240, 78, 35, 0.25);
    }
    .btn-outline {
      background: transparent;
      color: var(--flame-orange);
      border: 2px solid var(--flame-orange);
    }
    .btn-outline:hover {
      background-color: #FFF0EC;
      border-color: #C93D1A;
      color: #C93D1A;
      transform: translateY(-2px);
    }
    .text-link {
      color: var(--flame-orange);
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      gap: 0.25rem;
    }
    .text-link i {
      transition: transform 0.2s;
    }
    .text-link:hover {
      text-decoration: underline;
      text-decoration-color: var(--bright-yellow);
      text-underline-offset: 4px;
      color: #C93D1A;
    }
    .text-link:hover i {
      transform: translateX(4px);
    }
    /* Header nav */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--header-height);
      background-color: rgba(255,255,255,0.96);
      backdrop-filter: blur(10px);
      box-shadow: 0 2px 12px rgba(0,0,0,0.04);
      z-index: 1000;
      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: 0.6rem;
    }
    .logo-icon {
      font-size: 1.8rem;
      color: var(--flame-orange);
    }
    .logo-text {
      font-weight: 800;
      font-size: 1.5rem;
      color: var(--deep-charcoal);
      letter-spacing: -0.02em;
    }
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 2rem;
      list-style: none;
    }
    .nav-menu a {
      font-size: 0.95rem;
      font-weight: 550;
      color: var(--text-secondary);
      padding: 0.2rem 0;
      border-bottom: 2px solid transparent;
      transition: color 0.2s, border-color 0.2s;
    }
    .nav-menu a:hover,
    .nav-menu a.active {
      color: var(--flame-orange);
      border-bottom-color: var(--flame-orange);
    }
    .burger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
      padding: 0.5rem;
    }
    .burger span {
      display: block;
      width: 24px;
      height: 3px;
      background: var(--deep-charcoal);
      border-radius: 3px;
      transition: 0.3s;
    }
    .mobile-nav-overlay {
      display: none;
      position: fixed;
      top: var(--header-height);
      left: 0;
      width: 100%;
      height: calc(100vh - var(--header-height));
      background: rgba(30,30,30,0.98);
      z-index: 999;
      flex-direction: column;
      padding: 2rem;
      gap: 1.5rem;
    }
    .mobile-nav-overlay.is-open {
      display: flex;
    }
    .mobile-nav-overlay a {
      font-size: 1.3rem;
      color: #FFFFFF;
      font-weight: 600;
    }
    .mobile-nav-overlay a:hover {
      color: var(--bright-yellow);
    }
    @media (max-width: 768px) {
      .nav-menu { display: none; }
      .burger { display: flex; }
      .container { padding-left: 1.5rem; padding-right: 1.5rem; }
    }
    /* Sections components */
    section {
      padding: var(--spacing-xl) 0;
    }
    .section-title {
      font-size: 2.2rem;
      font-weight: 700;
      letter-spacing: -0.02em;
      margin-bottom: 0.5rem;
      color: var(--deep-charcoal);
    }
    .section-desc {
      font-size: 1.15rem;
      color: var(--text-secondary);
      max-width: 700px;
      margin: 0 auto 3rem auto;
      line-height: 1.7;
    }
    .hero-bg {
      background: linear-gradient(135deg, #1E1E1E 0%, #0B3B2F 100%);
      position: relative;
      overflow: hidden;
      padding: 6rem 0 4rem;
    }
    .hero-bg::after {
      content: '';
      position: absolute;
      right: -10%;
      top: 0;
      width: 450px;
      height: 450px;
      background: radial-gradient(circle, rgba(255,184,28,0.18) 0%, transparent 70%);
      border-radius: 50%;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 3rem;
      align-items: center;
      position: relative;
      z-index: 2;
    }
    .hero-left h1 {
      font-size: 3rem;
      font-weight: 800;
      letter-spacing: -0.02em;
      color: #FFFFFF;
      line-height: 1.3;
      margin-bottom: 1.5rem;
    }
    .hero-left .subtitle {
      font-size: 1.2rem;
      color: #E0E0E0;
      margin-bottom: 2.5rem;
    }
    .hero-buttons {
      display: flex;
      flex-wrap: wrap;
      gap: 1.2rem;
    }
    .hero-right img {
      border-radius: 24px;
      box-shadow: 0 24px 40px -12px rgba(0,0,0,0.5);
      transform: rotate(1deg);
      transition: transform 0.3s;
    }
    @media (max-width: 768px) {
      .hero-grid { grid-template-columns: 1fr; }
      .hero-right img { transform: none; }
      .hero-left h1 { font-size: 2.2rem; }
    }
    /* Cards grid */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, minmax(0,1fr));
      gap: 2rem;
    }
    .card {
      background: var(--card-bg);
      border-radius: var(--border-radius-card);
      padding: 2rem;
      box-shadow: var(--card-shadow);
      transition: transform 0.25s, box-shadow 0.3s;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--card-shadow-hover);
    }
    .service-card {
      display: flex;
      flex-direction: column;
    }
    .service-card img {
      aspect-ratio: 16 / 9;
      object-fit: cover;
      border-radius: 12px;
      margin-bottom: 1.5rem;
      filter: brightness(0.95);
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 2rem;
      background: #ECECE5;
      border-radius: 20px;
      padding: 2.5rem 2rem;
    }
    .stat-number {
      font-family: "Inter", "DIN Alternate", sans-serif;
      font-size: 2.8rem;
      font-weight: 800;
      color: var(--flame-orange);
    }
    .masonry-cases {
      columns: 3;
      column-gap: 1.5rem;
    }
    .case-item {
      break-inside: avoid;
      background: white;
      border-radius: var(--border-radius-card);
      overflow: hidden;
      box-shadow: var(--card-shadow);
      margin-bottom: 1.5rem;
      transition: transform 0.2s;
    }
    .case-item img {
      width: 100%;
      display: block;
    }
    .compare-table {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 2rem;
    }
    .compare-col {
      background: white;
      border-radius: 20px;
      padding: 2rem;
      border: 2px solid #E5E3DA;
    }
    .compare-col.recommended {
      border-color: var(--flame-orange);
      position: relative;
    }
    .badge-recommend {
      background: var(--bright-yellow);
      color: #1E1E1E;
      font-weight: 700;
      padding: 0.25rem 1.2rem;
      border-radius: 20px;
      font-size: 0.85rem;
      display: inline-block;
    }
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
      display: flex;
      flex-direction: column;
      gap: 0.8rem;
    }
    .faq-item {
      background: white;
      border-radius: 12px;
      padding: 1rem 1.5rem;
      cursor: pointer;
      box-shadow: 0 2px 8px rgba(0,0,0,0.02);
    }
    .faq-question {
      font-weight: 650;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: #444;
      line-height: 1.7;
    }
    .footer-main {
      background: #1E1E1E;
      color: #CDCBC5;
      padding: 3rem 0 1.5rem;
    }
    @media (max-width: 1024px) {
      .grid-3 { grid-template-columns: repeat(2,1fr); }
      .stats-grid { grid-template-columns: repeat(2,1fr); }
      .masonry-cases { columns: 2; }
      .compare-table { grid-template-columns: 1fr; }
    }
    @media (max-width: 520px) {
      .grid-3, .stats-grid, .masonry-cases { grid-template-columns: 1fr; columns: 1; }
      .section-title { font-size: 1.8rem; }
    }