/* roulang page: index */
:root {
      --primary-deep: #1A1A1A;
      --surface-light: #F5F4F0;
      --accent-cyan: #00C2E0;
      --text-body: #2C2C2C;
      --text-muted: #5A5A5A;
      --white: #FFFFFF;
      --border-cool: #E0DED8;
      --positive-green: #1F7A5C;
      --highlight-amber: #E69A2E;
      --error-red: #D32F2F;
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-large: 16px;
      --radius-capsule: 40px;
      --shadow-sm: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
      --font-number: "Inter", "PingFang SC", "Microsoft YaHei", sans-serif;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--white);
      color: var(--text-body);
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 32px;
    }
    /* 悬浮胶囊导航 */
    .nav-capsule {
      position: fixed;
      top: 24px;
      left: 50%;
      transform: translateX(-50%);
      width: auto;
      max-width: 600px;
      background: rgba(26,26,26,0.92);
      backdrop-filter: blur(16px);
      -webkit-backdrop-filter: blur(16px);
      border-radius: var(--radius-capsule);
      padding: 8px 24px;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 24px;
      z-index: 1000;
      box-shadow: 0 8px 20px rgba(0,0,0,0.25);
    }
    .nav-logo {
      font-weight: 700;
      font-size: 18px;
      color: var(--white);
      letter-spacing: 0.5px;
      margin-right: 8px;
      white-space: nowrap;
    }
    .nav-links {
      display: flex;
      gap: 20px;
      list-style: none;
      align-items: center;
    }
    .nav-links a {
      color: rgba(255,255,255,0.85);
      font-weight: 500;
      font-size: 14px;
      transition: color 0.2s;
      position: relative;
      padding-bottom: 4px;
      white-space: nowrap;
    }
    .nav-links a:hover {
      color: var(--accent-cyan);
    }
    .nav-links a.active {
      color: var(--accent-cyan);
    }
    .nav-links a.active::after {
      content: "";
      position: absolute;
      bottom: -2px;
      left: 50%;
      transform: translateX(-50%);
      width: 20px;
      height: 2px;
      background: var(--accent-cyan);
      border-radius: 2px;
    }
    /* 移动端导航调整为底部胶囊 */
    @media (max-width: 768px) {
      .nav-capsule {
        top: auto;
        bottom: 16px;
        left: 50%;
        transform: translateX(-50%);
        max-width: 95%;
        padding: 8px 16px;
        gap: 12px;
        border-radius: 32px;
        background: rgba(26,26,26,0.95);
      }
      .nav-logo {
        font-size: 16px;
      }
      .nav-links {
        gap: 12px;
      }
      .nav-links a {
        font-size: 13px;
      }
    }
    /* Hero */
    .hero {
      background-color: var(--primary-deep);
      background-image: radial-gradient(circle at 20% 30%, rgba(0,194,224,0.08) 0%, transparent 45%);
      min-height: 100vh;
      display: flex;
      align-items: center;
      position: relative;
      overflow: hidden;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 60px;
      flex-wrap: wrap;
    }
    .hero-left {
      flex: 1 1 500px;
    }
    .hero-right {
      flex: 1 1 400px;
      display: flex;
      flex-direction: column;
      gap: 20px;
      position: relative;
    }
    .hero h1 {
      font-size: 48px;
      line-height: 1.2;
      font-weight: 700;
      color: var(--white);
      letter-spacing: -0.02em;
      margin-bottom: 20px;
    }
    .hero-sub {
      font-size: 16px;
      color: #B0B0B0;
      max-width: 520px;
      margin-bottom: 32px;
      line-height: 1.6;
    }
    .btn-group {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--accent-cyan);
      color: var(--white);
      font-weight: 600;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      border: none;
      cursor: pointer;
      font-size: 16px;
      transition: background 0.2s, transform 0.2s, box-shadow 0.2s;
      display: inline-block;
      text-align: center;
    }
    .btn-primary:hover {
      background: #00A8C4;
      transform: translateY(-2px);
      box-shadow: 0 8px 18px rgba(0,194,224,0.3);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--accent-cyan);
      color: var(--accent-cyan);
      font-weight: 600;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      cursor: pointer;
      font-size: 16px;
      transition: all 0.2s;
      display: inline-block;
    }
    .btn-outline:hover {
      background: rgba(0,194,224,0.1);
      transform: translateY(-2px);
    }
    .metric-card {
      background: rgba(255,255,255,0.06);
      backdrop-filter: blur(8px);
      border: 1px solid rgba(255,255,255,0.1);
      border-radius: var(--radius-large);
      padding: 24px;
      color: var(--white);
      transition: transform 0.2s, box-shadow 0.2s;
    }
    .metric-number {
      font-family: var(--font-number);
      font-size: 42px;
      font-weight: 800;
      color: var(--accent-cyan);
      line-height: 1.1;
    }
    .metric-label {
      font-size: 14px;
      color: #B0B0B0;
      margin-top: 8px;
    }
    @media (max-width: 1024px) {
      .hero-grid {
        flex-direction: column;
        text-align: center;
      }
      .hero-left, .hero-right {
        flex: unset;
        width: 100%;
      }
      .hero h1 {
        font-size: 40px;
      }
    }
    @media (max-width: 520px) {
      .hero h1 {
        font-size: 32px;
      }
    }
    /* 通用板块 */
    section {
      padding: 80px 0;
    }
    .section-title {
      font-size: 36px;
      font-weight: 600;
      color: var(--text-body);
      margin-bottom: 16px;
      letter-spacing: -0.01em;
    }
    .section-sub {
      color: var(--text-muted);
      max-width: 700px;
      margin-bottom: 48px;
    }
    .bg-light {
      background: var(--surface-light);
    }
    /* 能力卡片 */
    .cards-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 32px;
    }
    .capability-card {
      background: var(--surface-light);
      border: 1px solid var(--border-cool);
      border-radius: var(--radius-card);
      padding: 32px;
      transition: all 0.2s;
      box-shadow: var(--shadow-sm);
    }
    .capability-card:hover {
      border-color: var(--accent-cyan);
      box-shadow: var(--shadow-md);
    }
    .capability-icon {
      width: 64px;
      height: 64px;
      margin-bottom: 20px;
      color: var(--accent-cyan);
      stroke-width: 1.5px;
    }
    .capability-card h3 {
      font-size: 22px;
      font-weight: 600;
      margin-bottom: 12px;
    }
    .text-link {
      color: var(--accent-cyan);
      font-weight: 500;
      display: inline-block;
      margin-top: 16px;
      position: relative;
    }
    .text-link::after {
      content: "";
      position: absolute;
      bottom: -2px;
      left: 0;
      width: 0;
      height: 1.5px;
      background: var(--accent-cyan);
      transition: width 0.2s;
    }
    .text-link:hover::after {
      width: 100%;
    }
    /* 数据看板 */
    .metrics-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 40px;
      text-align: center;
    }
    .metric-big {
      font-family: var(--font-number);
      font-size: 56px;
      font-weight: 800;
      color: var(--accent-cyan);
    }
    .trend-up {
      color: var(--positive-green);
      font-size: 13px;
    }
    /* 对比区块 */
    .contrast-row {
      display: flex;
      gap: 40px;
      align-items: center;
    }
    .contrast-col {
      flex: 1;
      background: var(--surface-light);
      border-radius: var(--radius-card);
      padding: 24px;
    }
    .contrast-img {
      border-radius: 12px;
      overflow: hidden;
      margin: 20px 0;
      border: 1px solid var(--border-cool);
    }
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-cool);
      padding: 20px 0;
    }
    .faq-question {
      font-size: 18px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease;
      color: var(--text-muted);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      margin-top: 12px;
    }
    .faq-icon {
      color: var(--accent-cyan);
      font-size: 24px;
    }
    /* CTA深色区 */
    .cta-dark {
      background: var(--primary-deep);
      color: var(--white);
    }
    .cta-form input, .cta-form textarea {
      width: 100%;
      padding: 14px;
      border-radius: var(--radius-btn);
      border: 1px solid #555;
      background: white;
      margin-bottom: 16px;
      font-family: inherit;
    }
    .cta-form input:focus {
      border-color: var(--accent-cyan);
      outline: none;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      background: #121212;
      color: #aaa;
      padding: 60px 0;
    }
    @media (max-width: 1024px) {
      .cards-grid, .metrics-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 768px) {
      .cards-grid, .metrics-grid, .footer-grid {
        grid-template-columns: 1fr;
      }
      .contrast-row {
        flex-direction: column;
      }
    }