/* roulang page: index */
:root {
      --color-primary: #C9A96E;
      --color-primary-hover: #DFC28A;
      --color-bg: #0D0D0D;
      --color-bg-alt: #1A1510;
      --color-surface: #1E1E1E;
      --color-surface-light: rgba(255,255,255,0.03);
      --color-text: #F5F0E8;
      --color-text-muted: #A89F91;
      --color-border: rgba(201,169,110,0.2);
      --color-border-active: rgba(201,169,110,0.6);
      --font-serif: 'Noto Serif SC', 'Source Han Serif SC', 'Times New Roman', serif;
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', system-ui, -apple-system, sans-serif;
      --sidebar-width: 240px;
      --radius-sm: 6px;
      --radius-md: 10px;
      --radius-lg: 16px;
      --shadow-card: 0 8px 32px rgba(201,169,110,0.08);
      --shadow-elevated: 0 20px 40px rgba(0,0,0,0.5);
      --transition-smooth: 0.3s cubic-bezier(0.25, 0.8, 0.25, 1.2);
    }

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

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

    body {
      font-family: var(--font-sans);
      background-color: var(--color-bg);
      color: var(--color-text);
      line-height: 1.6;
      display: flex;
      flex-direction: column;
      min-height: 100vh;
      overflow-x: hidden;
    }

    /* 左侧导航 App Shell */
    .app-sidebar {
      position: fixed;
      top: 0;
      left: 0;
      width: var(--sidebar-width);
      height: 100vh;
      background-color: #0A0A0A;
      display: flex;
      flex-direction: column;
      padding: 2.5rem 1.5rem;
      z-index: 1000;
      border-right: 1px solid rgba(201,169,110,0.15);
      transition: transform 0.3s ease;
    }

    .logo-area {
      margin-bottom: 3.5rem;
      font-family: var(--font-serif);
      font-weight: 700;
      font-size: 1.5rem;
      letter-spacing: 0.05em;
      color: var(--color-primary);
      text-align: left;
      line-height: 1.3;
      border-left: 4px solid var(--color-primary);
      padding-left: 1rem;
    }

    .nav-menu {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 0.8rem;
      flex: 1;
    }

    .nav-item {
      position: relative;
      padding-left: 1.2rem;
      transition: all 0.2s ease;
    }

    .nav-link {
      text-decoration: none;
      color: var(--color-text-muted);
      font-size: 1rem;
      font-weight: 400;
      letter-spacing: 0.03em;
      display: block;
      padding: 0.5rem 0;
      transition: color 0.2s;
      border-left: 2px solid transparent;
      margin-left: -1.2rem;
      padding-left: 1.2rem;
    }

    .nav-item:hover .nav-link,
    .nav-item.active .nav-link {
      color: var(--color-primary);
      border-left-color: var(--color-primary);
    }

    .nav-item.active .nav-link {
      font-weight: 500;
      border-left-width: 4px;
    }

    .mobile-header {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background-color: #0A0A0A;
      padding: 1rem 1.5rem;
      z-index: 999;
      justify-content: space-between;
      align-items: center;
      border-bottom: 1px solid rgba(201,169,110,0.2);
    }

    .hamburger {
      background: none;
      border: none;
      color: var(--color-primary);
      font-size: 1.8rem;
      cursor: pointer;
      line-height: 1;
    }

    .drawer-overlay {
      display: none;
    }

    /* 主内容区 */
    .main-content {
      margin-left: var(--sidebar-width);
      width: calc(100% - var(--sidebar-width));
      background: radial-gradient(circle at 20% 10%, #1E1610 0%, #0D0D0D 70%);
      transition: margin-left 0.3s;
    }

    section {
      padding: 5rem 2.5rem;
      max-width: 1200px;
      margin: 0 auto;
    }

    .container {
      width: 100%;
      max-width: 1100px;
      margin: 0 auto;
    }

    h1, h2, h3 {
      font-family: var(--font-serif);
      font-weight: 600;
    }

    h1 {
      font-size: 3.2rem;
      font-weight: 700;
      letter-spacing: 0.02em;
      line-height: 1.2;
      margin-bottom: 1.5rem;
      color: #F5F0E8;
    }

    h2 {
      font-size: 2.2rem;
      margin-bottom: 2.5rem;
      position: relative;
      display: inline-block;
      color: var(--color-text);
    }

    h2::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: -8px;
      width: 60%;
      height: 2px;
      background: linear-gradient(to right, var(--color-primary), transparent);
    }

    h3 {
      font-size: 1.4rem;
      color: var(--color-text);
    }

    .btn {
      display: inline-block;
      padding: 0.9rem 2.2rem;
      border-radius: var(--radius-sm);
      font-weight: 500;
      text-decoration: none;
      transition: all 0.3s ease;
      letter-spacing: 0.03em;
      cursor: pointer;
      border: 1px solid transparent;
    }

    .btn-primary {
      background-color: var(--color-primary);
      color: #0A0A0A;
      box-shadow: 0 4px 14px rgba(201,169,110,0.3);
    }

    .btn-primary:hover {
      background-color: var(--color-primary-hover);
      box-shadow: 0 8px 22px rgba(201,169,110,0.5);
      transform: translateY(-2px);
    }

    .btn-outline {
      border: 1px solid var(--color-primary);
      color: var(--color-primary);
      background: transparent;
    }

    .btn-outline:hover {
      background-color: rgba(201,169,110,0.1);
      border-color: var(--color-primary-hover);
      color: var(--color-primary-hover);
    }

    /* Hero */
    #hero {
      height: 100vh;
      display: flex;
      align-items: center;
      position: relative;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center 30%;
      background-repeat: no-repeat;
      padding: 0 2.5rem;
    }

    #hero::before {
      content: '';
      position: absolute;
      inset: 0;
      background: linear-gradient(90deg, rgba(13,13,13,0.85) 0%, rgba(26,21,16,0.7) 60%, rgba(13,13,13,0.4) 100%);
      z-index: 1;
    }

    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 700px;
    }

    .hero-subtitle {
      font-size: 1.2rem;
      color: var(--color-text-muted);
      margin-bottom: 2.5rem;
      letter-spacing: 0.1em;
      border-left: 3px solid var(--color-primary);
      padding-left: 1.5rem;
    }

    .hero-buttons {
      display: flex;
      gap: 1.2rem;
      flex-wrap: wrap;
    }

    /* 服务卡片 - 不对称栅格 */
    .services-grid {
      display: grid;
      grid-template-columns: 1.2fr 0.8fr 1fr;
      gap: 1.8rem;
      margin-top: 2rem;
    }

    .service-card {
      background: rgba(30,30,30,0.6);
      backdrop-filter: blur(2px);
      border: 1px solid var(--color-border);
      padding: 2rem 1.8rem;
      border-radius: var(--radius-md);
      transition: all 0.3s ease;
      display: flex;
      flex-direction: column;
      gap: 1rem;
    }

    .service-card:hover {
      border-color: var(--color-primary);
      transform: translateY(-6px);
      box-shadow: var(--shadow-card);
      background: rgba(20,20,20,0.8);
    }

    .service-icon {
      font-size: 2.2rem;
      color: var(--color-primary);
      margin-bottom: 0.3rem;
    }

    /* 优势数据 */
    .advantages-grid {
      display: flex;
      justify-content: space-between;
      gap: 2rem;
      flex-wrap: wrap;
    }

    .stat-item {
      flex: 1;
      min-width: 180px;
      text-align: left;
    }

    .stat-number {
      font-size: 2.8rem;
      font-weight: 700;
      color: var(--color-primary);
      line-height: 1.1;
      margin-bottom: 0.4rem;
      position: relative;
      display: inline-block;
    }

    .stat-number::after {
      content: '';
      position: absolute;
      bottom: -6px;
      left: 0;
      width: 40px;
      height: 2px;
      background: var(--color-primary);
    }

    .stat-label {
      color: var(--color-text-muted);
      font-size: 1rem;
    }

    /* 案例卡片 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 2rem;
    }

    .case-card {
      background: #1A1A1A;
      border-radius: var(--radius-md);
      overflow: hidden;
      border: 1px solid transparent;
      transition: 0.3s;
    }

    .case-card:hover {
      border-color: var(--color-primary);
      box-shadow: var(--shadow-elevated);
    }

    .case-img {
      width: 100%;
      height: 200px;
      object-fit: cover;
      display: block;
    }

    .case-info {
      padding: 1.5rem;
    }

    .case-tag {
      color: var(--color-primary);
      font-size: 0.8rem;
      letter-spacing: 0.05em;
      margin-bottom: 0.4rem;
    }

    /* 方案图文 */
    .solution-row {
      display: flex;
      align-items: center;
      gap: 3rem;
      margin-bottom: 4rem;
    }

    .solution-row.reverse {
      flex-direction: row-reverse;
    }

    .solution-text {
      flex: 1;
    }

    .solution-img {
      flex: 1;
      border-radius: var(--radius-md);
      height: 280px;
      object-fit: cover;
      border: 1px solid var(--color-border);
    }

    /* FAQ */
    .faq-item {
      background: rgba(30,30,30,0.7);
      border: 1px solid var(--color-border);
      border-radius: var(--radius-sm);
      margin-bottom: 1rem;
      overflow: hidden;
    }

    .faq-question {
      padding: 1.2rem 1.8rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      font-weight: 500;
      background: transparent;
      border: none;
      color: var(--color-text);
      width: 100%;
      text-align: left;
      font-size: 1.05rem;
    }

    .faq-icon {
      font-size: 1.5rem;
      color: var(--color-primary);
      transition: transform 0.3s;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.3s;
      background: rgba(0,0,0,0.3);
      padding: 0 1.8rem;
    }

    .faq-item.open .faq-answer {
      max-height: 180px;
      padding: 1rem 1.8rem;
    }

    .faq-item.open .faq-icon {
      transform: rotate(45deg);
    }

    /* 联系表单 */
    .contact-wrapper {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 2.5rem;
      background: rgba(20,20,20,0.5);
      border: 1px solid var(--color-border);
      border-radius: var(--radius-lg);
      padding: 2.5rem;
    }

    .input-group input, .input-group textarea {
      width: 100%;
      background: #1E1E1E;
      border: 1px solid rgba(201,169,110,0.3);
      padding: 0.9rem;
      color: white;
      border-radius: var(--radius-sm);
      margin-bottom: 1.2rem;
      outline: none;
      transition: 0.2s;
    }

    .input-group input:focus {
      border-color: var(--color-primary);
    }

    footer {
      background: #0A0A0A;
      padding: 2.5rem;
      margin-left: var(--sidebar-width);
      display: flex;
      justify-content: space-between;
      flex-wrap: wrap;
      border-top: 1px solid var(--color-border);
    }

    @media (max-width: 1024px) {
      .app-sidebar {
        transform: translateX(-100%);
      }
      .app-sidebar.open {
        transform: translateX(0);
      }
      .main-content, footer {
        margin-left: 0;
        width: 100%;
      }
      .mobile-header {
        display: flex;
      }
      .services-grid {
        grid-template-columns: 1fr 1fr;
      }
    }

    @media (max-width: 640px) {
      h1 { font-size: 2rem; }
      .services-grid, .cases-grid { grid-template-columns: 1fr; }
      .solution-row { flex-direction: column; }
      .contact-wrapper { grid-template-columns: 1fr; }
    }