/* roulang page: index */
:root {
      --primary-deep: #2B3A2B;
      --accent-orange: #E85D04;
      --bg-warm: #F7F5F0;
      --bg-dark: #1E1E1E;
      --text-main: #1C1C1C;
      --text-secondary: #5A5A5A;
      --white: #FFFFFF;
      --border-subtle: rgba(0,0,0,0.04);
      --border-light: rgba(255,255,255,0.15);
      
      --font-heading: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
      --font-body: 'Inter', 'Noto Serif SC', 'Source Han Serif SC', serif;
      --font-ui: 'Noto Sans SC', sans-serif;
      
      --radius-lg: 12px;
      --radius-md: 8px;
      --radius-sm: 6px;
      --shadow-card: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-hover: 0 8px 28px rgba(0,0,0,0.08);
      
      --max-width: 1280px;
      --gap-section: 120px;
      --gap-inner: 80px;
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: var(--font-ui);
      background-color: var(--bg-warm);
      color: var(--text-main);
      line-height: 1.7;
      font-size: 17px;
      -webkit-font-smoothing: antialiased;
    }

    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 32px;
    }

    /* 标题级联 */
    h1, h2, h3 {
      font-family: var(--font-heading);
      letter-spacing: -0.02em;
      color: var(--text-main);
    }

    h1 { font-size: clamp(36px, 5.5vw, 58px); font-weight: 800; line-height: 1.25; }
    h2 { font-size: clamp(28px, 3.8vw, 40px); font-weight: 700; line-height: 1.3; margin-bottom: 1.2rem; }
    h3 { font-size: 22px; font-weight: 600; line-height: 1.35; }

    p {
      font-family: var(--font-body);
      color: var(--text-secondary);
      line-height: 1.8;
      margin-bottom: 1.5rem;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: all 0.25s ease;
    }

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

    /* 按钮系统 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 14px 32px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 16px;
      letter-spacing: 0.02em;
      transition: all 0.25s ease;
      cursor: pointer;
      border: none;
      font-family: var(--font-ui);
      text-align: center;
    }

    .btn-primary {
      background: var(--accent-orange);
      color: white;
      box-shadow: 0 4px 10px rgba(232, 93, 4, 0.2);
    }
    .btn-primary:hover {
      background: #C94D00;
      transform: scale(1.03);
      box-shadow: 0 6px 16px rgba(232, 93, 4, 0.35);
    }

    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary-deep);
      color: var(--primary-deep);
    }
    .btn-outline:hover {
      background: rgba(43,58,43,0.06);
      transform: translateY(-2px);
    }

    .text-link {
      color: var(--accent-orange);
      font-weight: 600;
      border-bottom: 1px solid currentColor;
      transition: border-width 0.2s;
    }
    .text-link:hover {
      border-bottom-width: 2px;
    }

    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 100;
      padding: 20px 0;
      transition: background 0.3s, box-shadow 0.3s, padding 0.3s;
      background: rgba(247, 245, 240, 0.85);
      backdrop-filter: blur(12px);
    }
    .site-header.scrolled {
      background: rgba(255,255,255, 0.94);
      box-shadow: 0 4px 20px rgba(0,0,0,0.05);
      padding: 14px 0;
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 32px;
    }

    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-family: var(--font-heading);
      font-weight: 800;
      font-size: 24px;
      color: var(--primary-deep);
      letter-spacing: -0.01em;
    }
    .logo-icon {
      width: 34px;
      height: 34px;
      background: var(--primary-deep);
      mask: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><path d="M40 78 C20 70 12 42 22 28 C32 18 52 24 58 38 C62 16 78 8 82 24 C86 36 68 52 48 60 C44 74 54 82 68 78 C62 88 46 85 40 78Z" fill="none" stroke="black" stroke-width="20" stroke-linecap="round"/></svg>') no-repeat center;
      mask-size: contain;
      background: var(--primary-deep);
    }

    .nav-links {
      display: flex;
      gap: 36px;
      font-weight: 500;
      color: var(--text-main);
    }
    .nav-links a {
      position: relative;
      padding: 4px 0;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent-orange);
      transition: width 0.25s;
    }
    .nav-links a:hover::after {
      width: 100%;
    }
    .mobile-menu-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 24px;
      color: var(--primary-deep);
    }

    /* Hero */
    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: linear-gradient(180deg, rgba(43,58,43,0) 30%, rgba(43,58,43,0.15)), url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      background-attachment: scroll;
      position: relative;
      margin-bottom: var(--gap-section);
    }
    .hero-content {
      max-width: 700px;
      padding-top: 80px;
    }
    .hero h1 {
      color: var(--text-main);
      margin-bottom: 24px;
    }
    .hero .subtitle {
      font-size: 20px;
      color: var(--text-secondary);
      margin-bottom: 40px;
      font-family: var(--font-body);
    }
    .hero-actions {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }

    /* 通用板块 */
    .section {
      margin-bottom: var(--gap-section);
    }
    .section-title {
      text-align: left;
      margin-bottom: 48px;
    }

    /* 核心优势 - 非对称栅格 */
    .advantages-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 32px;
    }
    .advantage-card {
      background: var(--white);
      padding: 36px 32px;
      border-radius: var(--radius-lg);
      border: 1px solid var(--border-subtle);
      transition: all 0.3s;
    }
    .advantage-card:hover {
      transform: translateY(-5px);
      box-shadow: var(--shadow-hover);
    }
    .adv-icon {
      font-size: 32px;
      color: var(--accent-orange);
      margin-bottom: 18px;
    }
    .advantage-card h3 {
      margin-bottom: 12px;
    }

    /* 解决方案左右交替 */
    .solution-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
    }
    .solution-row.reverse {
      flex-direction: row-reverse;
    }
    .solution-text {
      flex: 1;
    }
    .solution-text .tag {
      display: inline-block;
      background: rgba(232,93,4,0.08);
      color: var(--accent-orange);
      padding: 6px 14px;
      border-radius: 20px;
      font-size: 14px;
      font-weight: 600;
      margin-bottom: 20px;
    }
    .solution-image {
      flex: 1.1;
      min-width: 300px;
    }
    .data-highlight {
      font-size: 36px;
      font-weight: 800;
      color: var(--accent-orange);
      line-height: 1.2;
    }

    /* 数据区块 */
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 28px;
    }
    .stat-item {
      text-align: center;
      background: var(--white);
      padding: 32px 16px;
      border-radius: var(--radius-md);
    }
    .stat-number {
      font-size: 48px;
      font-weight: 800;
      color: var(--accent-orange);
    }

    /* 证言 */
    .testimonial-cards {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 40px;
    }
    .testimonial {
      background: var(--white);
      padding: 40px;
      border-radius: var(--radius-lg);
      position: relative;
    }
    .quote-icon {
      font-size: 48px;
      color: rgba(43,58,43,0.25);
      position: absolute;
      top: 20px;
      left: 30px;
    }
    .testimonial-text {
      font-family: var(--font-body);
      font-style: italic;
      font-size: 18px;
      margin: 10px 0 24px;
      color: var(--text-main);
    }
    .author-line {
      display: flex;
      align-items: center;
      gap: 12px;
      border-top: 1px solid var(--border-subtle);
      padding-top: 20px;
    }
    .author-line strong {
      color: var(--primary-deep);
    }

    /* FAQ */
    .faq-list {
      max-width: 900px;
    }
    .faq-item {
      border-bottom: 1px solid rgba(0,0,0,0.08);
      margin-bottom: 8px;
    }
    .faq-question {
      width: 100%;
      text-align: left;
      background: none;
      border: none;
      padding: 22px 0;
      font-size: 18px;
      font-weight: 600;
      color: var(--primary-deep);
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s;
      background: #F9F8F6;
      border-radius: 0 0 8px 8px;
    }
    .faq-answer p {
      padding: 0 20px;
      margin: 0;
      color: var(--text-secondary);
    }
    .faq-item.active .faq-answer {
      max-height: 150px;
      padding: 20px 0;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }

    /* CTA 区块 */
    .cta-full {
      background: linear-gradient(135deg, #1E1E1E 0%, #2B3A2B 100%);
      border-radius: var(--radius-lg);
      padding: 80px 40px;
      text-align: center;
      color: white;
    }
    .cta-full h2 {
      color: white;
    }

    /* 页脚 */
    .footer {
      background: var(--bg-dark);
      color: #B0B0B0;
      padding: 70px 0 30px;
      margin-top: 100px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1.2fr 1fr;
      gap: 48px;
    }
    .footer a:hover { color: var(--accent-orange); }

    @media (max-width: 1024px) {
      .container { padding: 0 24px; }
      .stats-grid { grid-template-columns: repeat(2,1fr); }
      .solution-row { flex-direction: column; gap: 32px; }
      .solution-row.reverse { flex-direction: column; }
    }
    @media (max-width: 768px) {
      .nav-links, .header-cta { display: none; }
      .mobile-menu-toggle { display: block; }
      .footer-grid { grid-template-columns: 1fr; }
      .testimonial-cards { grid-template-columns: 1fr; }
      .advantages-grid { grid-template-columns: 1fr; }
    }