/* roulang page: index */
:root {
      --primary-deep: #0B0C10;
      --card-bg: #15171E;
      --accent-purple: #6C3CF0;
      --accent-cyan: #00F0FF;
      --text-dim: #B0B5C0;
      --text-white: #FFFFFF;
      --border-glow: rgba(108, 60, 240, 0.25);
      --radius-lg: 16px;
      --radius-md: 12px;
      --radius-sm: 8px;
      --shadow-glow: 0 0 20px rgba(108, 60, 240, 0.5);
      --font-mono: 'Roboto Mono', 'SF Mono', 'Cascadia Code', monospace;
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --transition-fast: 0.2s cubic-bezier(0.23, 1, 0.32, 1);
    }

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

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

    body {
      background-color: var(--primary-deep);
      color: var(--text-dim);
      font-family: var(--font-sans);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
      background-image: radial-gradient(circle at 25% 0%, rgba(108, 60, 240, 0.08) 0%, transparent 35%);
    }

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 2rem;
    }

    /* 导航 */
    .nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: rgba(11, 12, 16, 0.82);
      backdrop-filter: blur(18px);
      border-bottom: 1px solid rgba(108, 60, 240, 0.25);
      transition: padding 0.25s ease, box-shadow 0.25s ease;
      padding: 0.9rem 0;
    }

    .nav.scrolled {
      padding: 0.6rem 0;
      box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.7);
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 2rem;
    }

    .logo {
      font-size: 1.8rem;
      font-weight: 800;
      letter-spacing: 1px;
      background: linear-gradient(135deg, var(--accent-cyan) 0%, var(--accent-purple) 80%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      text-decoration: none;
      display: flex;
      align-items: center;
      gap: 0.2rem;
    }

    .logo span {
      font-weight: 600;
      font-size: 1.4rem;
      background: none;
      -webkit-text-fill-color: var(--text-white);
      color: var(--text-white);
      margin-left: 0.2rem;
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 2.5rem;
    }

    .nav-links a {
      color: var(--text-dim);
      text-decoration: none;
      font-weight: 500;
      font-size: 0.95rem;
      letter-spacing: 0.4px;
      transition: color 0.2s;
      position: relative;
    }

    .nav-links a:hover,
    .nav-links a.active {
      color: var(--accent-cyan);
    }

    .btn-nav {
      background: var(--accent-purple);
      color: white;
      padding: 0.6rem 1.8rem;
      border-radius: 2rem;
      font-weight: 600;
      font-size: 0.9rem;
      text-decoration: none;
      transition: background 0.25s, box-shadow 0.25s;
      border: none;
      cursor: pointer;
      display: inline-block;
    }

    .btn-nav:hover {
      background: #8455FF;
      box-shadow: var(--shadow-glow);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      cursor: pointer;
      gap: 6px;
    }

    .hamburger span {
      width: 26px;
      height: 2px;
      background: var(--text-white);
      transition: 0.2s;
    }

    /* 移动端导航 */
    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 75%;
        max-width: 320px;
        height: 100vh;
        background: rgba(11, 12, 16, 0.96);
        backdrop-filter: blur(24px);
        flex-direction: column;
        justify-content: center;
        gap: 2.8rem;
        transition: right 0.35s ease;
        border-left: 1px solid var(--border-glow);
        padding: 2rem;
      }
      .nav-links.active {
        right: 0;
      }
      .hamburger {
        display: flex;
        z-index: 1100;
      }
      .btn-nav {
        padding: 0.8rem 2.2rem;
      }
    }

    /* Hero */
    .hero {
      padding: 9rem 0 5rem;
      display: flex;
      align-items: center;
      gap: 3rem;
      flex-wrap: wrap;
    }

    .hero-content {
      flex: 1 1 50%;
    }

    .hero-title {
      font-size: clamp(2.4rem, 6vw, 3.6rem);
      font-weight: 800;
      line-height: 1.2;
      margin-bottom: 1.5rem;
      color: var(--text-white);
    }

    .gradient-text {
      background: linear-gradient(to right, var(--accent-cyan), var(--accent-purple));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }

    .hero-sub {
      font-size: 1.2rem;
      color: var(--text-dim);
      margin-bottom: 2.5rem;
      max-width: 500px;
    }

    .btn-group {
      display: flex;
      gap: 1.2rem;
      flex-wrap: wrap;
    }

    .btn-primary {
      background: var(--accent-purple);
      color: white;
      padding: 0.9rem 2.4rem;
      border-radius: 2rem;
      font-weight: 700;
      text-decoration: none;
      display: inline-block;
      transition: 0.3s;
      border: none;
      letter-spacing: 1px;
      box-shadow: 0 0 15px rgba(108, 60, 240, 0.5);
    }

    .btn-primary:hover {
      background: #8A5CFF;
      box-shadow: 0 0 28px rgba(108, 60, 240, 0.8);
      transform: translateY(-2px);
    }

    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--accent-cyan);
      color: var(--accent-cyan);
      padding: 0.9rem 2.4rem;
      border-radius: 2rem;
      font-weight: 700;
      text-decoration: none;
      transition: 0.3s;
    }

    .btn-outline:hover {
      background: var(--accent-cyan);
      color: var(--primary-deep);
    }

    .hero-image {
      flex: 1 1 40%;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      min-height: 320px;
      border-radius: var(--radius-lg);
      position: relative;
      box-shadow: 0 0 35px rgba(0, 240, 255, 0.25);
    }

    .hero-image::after {
      content: '';
      position: absolute;
      inset: 0;
      background: rgba(11, 12, 16, 0.55);
      backdrop-filter: blur(1px);
      border-radius: inherit;
    }

    /* 通用板块 */
    section {
      padding: 5rem 0;
    }

    .section-title {
      font-size: 2.2rem;
      font-weight: 700;
      color: var(--text-white);
      margin-bottom: 1rem;
    }

    .section-sub {
      color: var(--text-dim);
      margin-bottom: 3rem;
      font-size: 1.1rem;
    }

    /* 优势区 非对称 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 2rem;
    }

    .feature-item {
      background: var(--card-bg);
      border-radius: var(--radius-lg);
      padding: 2rem;
      border: 1px solid rgba(108, 60, 240, 0.18);
      transition: all 0.3s;
    }

    .feature-item:hover {
      transform: translateY(-6px);
      border-color: var(--accent-cyan);
    }

    .feature-icon {
      font-size: 2.2rem;
      color: var(--accent-cyan);
      margin-bottom: 1rem;
    }

    /* 功能交错卡片 */
    .function-row {
      display: flex;
      gap: 2rem;
      align-items: center;
      margin-bottom: 4rem;
      flex-wrap: wrap;
    }

    .func-text {
      flex: 1;
    }

    .func-img {
      flex: 1;
      background: url('/assets/images/coverpic/cover-2.webp') center/cover;
      height: 240px;
      border-radius: var(--radius-md);
    }

    .tag {
      background: rgba(0, 240, 255, 0.1);
      color: var(--accent-cyan);
      padding: 0.25rem 1rem;
      border-radius: 2rem;
      font-size: 0.8rem;
      font-weight: 600;
    }

    /* 数据墙 */
    .stats-grid {
      display: flex;
      justify-content: space-around;
      flex-wrap: wrap;
      gap: 2rem;
      text-align: center;
    }

    .stat-number {
      font-size: 3rem;
      font-weight: 800;
      font-family: var(--font-mono);
      color: var(--accent-cyan);
    }

    /* FAQ */
    .faq-item {
      background: var(--card-bg);
      border-radius: var(--radius-md);
      margin-bottom: 12px;
      padding: 1.2rem 1.8rem;
      cursor: pointer;
      border-left: 4px solid var(--accent-purple);
    }

    .faq-question {
      font-weight: 600;
      color: white;
      display: flex;
      justify-content: space-between;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-dim);
    }

    /* CTA */
    .cta-band {
      background: linear-gradient(135deg, #6C3CF0 0%, #0B0C10 90%);
      border-radius: var(--radius-lg);
      padding: 3.5rem;
      text-align: center;
    }

    footer {
      background: #0A0B0F;
      border-top: 1px solid var(--accent-cyan);
      padding: 3rem 0;
      color: var(--text-dim);
    }

    @media (max-width: 768px) {
      .features-grid { grid-template-columns: 1fr; }
      .hero { flex-direction: column; }
      .function-row { flex-direction: column; }
    }