/* roulang page: index */
:root {
      --deep-rock: #2B2D2F;
      --rock-dark: #1A1C1E;
      --zhibo-copper: #C89B5E;
      --copper-deep: #A67B4A;
      --mist-white: #F7F5F0;
      --soft-gray-bg: #F0EEE9;
      --text-dark: #1A1C1E;
      --text-body: #4A4D50;
      --text-muted: rgba(247,245,240,0.7);
      --border-light: #EAE7E2;
      --border-copper: rgba(200,155,94,0.3);
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --font-mono: 'SF Mono', 'Menlo', 'Monaco', monospace;
      --radius-md: 8px;
      --shadow-sm: 0 2px 8px rgba(43,45,47,0.06);
      --shadow-hover: 0 8px 24px rgba(43,45,47,0.10);
      --transition-base: 0.25s ease;
      --sidebar-width: 240px;
    }
    * {
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--mist-white);
      color: var(--text-body);
      line-height: 1.6;
      margin: 0;
      padding: 0;
      font-size: 16px;
      overflow-x: hidden;
    }
    h1, h2, h3, h4 {
      font-family: var(--font-sans);
      color: var(--text-dark);
      font-weight: 600;
    }
    h1 {
      font-size: 48px;
      line-height: 1.2;
      font-weight: 600;
    }
    h2 {
      font-size: 36px;
      line-height: 1.25;
      margin-bottom: 1.5rem;
    }
    h3 {
      font-size: 22px;
      line-height: 1.4;
      font-weight: 500;
    }
    .text-mono {
      font-family: var(--font-mono);
    }
    a {
      color: var(--zhibo-copper);
      text-decoration: none;
      transition: var(--transition-base);
    }
    a:hover {
      color: var(--copper-deep);
    }
    .btn-primary-custom {
      background-color: var(--zhibo-copper);
      border: none;
      color: white;
      font-weight: 500;
      padding: 14px 32px;
      border-radius: var(--radius-md);
      transition: var(--transition-base);
      letter-spacing: 0.5px;
    }
    .btn-primary-custom:hover {
      background-color: var(--copper-deep);
      color: white;
      transform: translateY(-1px);
      box-shadow: var(--shadow-hover);
    }
    .btn-outline-copper {
      background: transparent;
      border: 1.5px solid var(--zhibo-copper);
      color: var(--zhibo-copper);
      font-weight: 500;
      padding: 14px 32px;
      border-radius: var(--radius-md);
      transition: var(--transition-base);
    }
    .btn-outline-copper:hover {
      background-color: rgba(200,155,94,0.08);
      color: var(--copper-deep);
      border-color: var(--copper-deep);
    }
    .section-padding {
      padding: 100px 0;
    }
    @media (max-width: 768px) {
      .section-padding {
        padding: 60px 0;
      }
      h1 {
        font-size: 32px;
      }
      h2 {
        font-size: 26px;
      }
      h3 {
        font-size: 20px;
      }
    }
    /* 左侧导航 App Shell */
    .app-sidebar {
      position: fixed;
      left: 0;
      top: 0;
      width: var(--sidebar-width);
      height: 100vh;
      background-color: var(--deep-rock);
      color: var(--mist-white);
      display: flex;
      flex-direction: column;
      z-index: 1030;
      box-shadow: 2px 0 15px rgba(0,0,0,0.08);
    }
    .sidebar-brand {
      height: 80px;
      display: flex;
      align-items: center;
      padding: 0 24px;
      border-bottom: 1px solid rgba(247,245,240,0.1);
    }
    .logo-icon {
      width: 32px;
      height: 32px;
      background: linear-gradient(135deg, var(--zhibo-copper) 0%, #8b6b3c 100%);
      border-radius: 6px;
      margin-right: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      color: white;
      font-size: 18px;
    }
    .brand-text {
      font-weight: 600;
      font-size: 20px;
      color: var(--mist-white);
      letter-spacing: 1px;
    }
    .sidebar-nav {
      flex: 1;
      padding: 32px 0;
      display: flex;
      flex-direction: column;
    }
    .nav-item-custom {
      display: flex;
      align-items: center;
      padding: 14px 24px;
      color: rgba(247,245,240,0.8);
      transition: var(--transition-base);
      border-left: 3px solid transparent;
      font-size: 16px;
      margin-bottom: 4px;
    }
    .nav-item-custom i {
      width: 24px;
      color: var(--zhibo-copper);
      font-size: 18px;
      margin-right: 12px;
    }
    .nav-item-custom:hover {
      background: rgba(200,155,94,0.1);
      color: white;
      border-left-color: var(--zhibo-copper);
    }
    .nav-item-custom.active {
      border-left-color: var(--zhibo-copper);
      color: white;
      background: rgba(200,155,94,0.08);
    }
    .sidebar-footer {
      padding: 24px;
      font-size: 12px;
      color: rgba(247,245,240,0.5);
      border-top: 1px solid rgba(247,245,240,0.1);
    }
    .main-content {
      margin-left: var(--sidebar-width);
      width: calc(100% - var(--sidebar-width));
      background: var(--mist-white);
    }
    /* 移动端顶部栏 */
    .mobile-topbar {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 64px;
      background: var(--deep-rock);
      z-index: 1040;
      align-items: center;
      justify-content: space-between;
      padding: 0 20px;
    }
    .mobile-drawer {
      position: fixed;
      top: 0;
      right: -100%;
      width: 280px;
      height: 100vh;
      background: var(--deep-rock);
      z-index: 1050;
      transition: right 0.3s ease;
      padding: 24px;
      display: flex;
      flex-direction: column;
    }
    .mobile-drawer.open {
      right: 0;
    }
    @media (max-width: 991px) {
      .app-sidebar {
        display: none;
      }
      .mobile-topbar {
        display: flex;
      }
      .main-content {
        margin-left: 0;
        width: 100%;
        padding-top: 64px;
      }
    }
    @media (min-width: 992px) and (max-width: 1199px) {
      .app-sidebar {
        width: 200px;
      }
      .main-content {
        margin-left: 200px;
        width: calc(100% - 200px);
      }
    }
    /* 卡片系统 */
    .card-custom {
      background: #FFFFFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-sm);
      transition: var(--transition-base);
      overflow: hidden;
    }
    .card-custom:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .solution-card {
      padding: 32px;
      position: relative;
    }
    .watermark-number {
      font-size: 48px;
      font-weight: 700;
      color: var(--zhibo-copper);
      opacity: 0.15;
      position: absolute;
      top: 16px;
      left: 24px;
    }
    .testimonial-card {
      border-left: 4px solid var(--zhibo-copper);
      padding: 24px;
      background: white;
      margin-bottom: 24px;
    }
    /* FAQ */
    .accordion-custom .accordion-button {
      background: transparent;
      font-weight: 500;
      color: var(--deep-rock);
      box-shadow: none;
      border-bottom: 1px solid var(--border-light);
      padding: 20px 0;
    }
    .accordion-custom .accordion-button:not(.collapsed) {
      background-color: #FAF9F7;
      color: var(--deep-rock);
    }
    .footer-dark {
      background-color: var(--rock-dark);
      color: var(--text-muted);
    }
    .footer-dark a {
      color: rgba(247,245,240,0.6);
    }
    .footer-dark a:hover {
      color: var(--zhibo-copper);
    }
    .img-grayscale {
      filter: grayscale(100%);
      transition: filter 0.4s ease;
    }
    .card-custom:hover .img-grayscale {
      filter: grayscale(0%);
    }