/* roulang page: index */
/* ----- 设计变量与全局重置 ----- */
    :root {
      --primary: #7C3AED;
      --primary-glow: rgba(124, 58, 237, 0.6);
      --accent: #00F0FF;
      --accent-glow: rgba(0, 240, 255, 0.5);
      --cta: #FF6B35;
      --cta-hover: #E55A2B;
      
      --bg-deep: #0A0A0F;
      --bg-card: #16161F;
      --bg-light-section: #F5F3FF;
      --bg-overlay: rgba(10, 10, 15, 0.85);
      
      --text-primary: #EAEAEF;
      --text-secondary: #9CA3AF;
      --text-on-dark: #FFFFFF;
      --text-on-light: #1F1A2E;
      
      --border-subtle: rgba(124, 58, 237, 0.2);
      --border-card: rgba(124, 58, 237, 0.15);
      --radius-md: 16px;
      --radius-sm: 8px;
      --shadow-card: 0 4px 24px rgba(124, 58, 237, 0.08);
      --shadow-hover: 0 12px 36px rgba(0, 240, 255, 0.18);
      --transition: 0.25s cubic-bezier(0.2, 0, 0.2, 1);
      
      --font-sans: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
      --font-mono: "Inter", "SF Pro Display", system-ui, sans-serif;
    }

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

    html {
      scroll-behavior: smooth;
      background-color: var(--bg-deep);
    }

    body {
      font-family: var(--font-sans);
      line-height: 1.6;
      color: var(--text-primary);
      background-color: var(--bg-deep);
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }

    img {
      max-width: 100%;
      height: auto;
      display: block;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }

    h1, h2, h3, h4 {
      font-weight: 700;
      margin-top: 0;
    }

    .container {
      width: 100%;
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: clamp(16px, 5vw, 40px);
      padding-right: clamp(16px, 5vw, 40px);
    }

    /* ----- 导航栏（沉浸式） ----- */
    .navbar {
      position: sticky;
      top: 0;
      left: 0;
      width: 100%;
      background: var(--bg-overlay);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-bottom: 1px solid var(--border-subtle);
      z-index: 100;
      padding: 16px 0;
      transition: var(--transition);
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 clamp(16px, 5vw, 40px);
    }

    .logo {
      font-size: 1.8rem;
      font-weight: 800;
      color: #fff;
      display: flex;
      align-items: center;
      gap: 6px;
      letter-spacing: -0.02em;
    }
    .logo .icon-lightning {
      font-size: 2rem;
      color: var(--accent);
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }
    .nav-links a {
      font-weight: 500;
      color: var(--text-secondary);
      position: relative;
      font-size: 0.95rem;
    }
    .nav-links a::after {
      content: "";
      position: absolute;
      bottom: -6px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent);
      transition: width 0.3s ease;
    }
    .nav-links a:hover {
      color: var(--accent);
    }
    .nav-links a:hover::after {
      width: 100%;
    }

    .btn-primary-small {
      background: var(--cta);
      color: white;
      font-weight: 700;
      padding: 10px 24px;
      border-radius: var(--radius-sm);
      font-size: 0.9rem;
      border: none;
      cursor: pointer;
      transition: all 0.3s;
      white-space: nowrap;
    }
    .btn-primary-small:hover {
      background: var(--cta-hover);
      box-shadow: 0 0 20px rgba(255, 107, 53, 0.5);
    }

    .menu-toggle {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: transparent;
      border: none;
      cursor: pointer;
      padding: 4px;
    }
    .menu-toggle span {
      width: 28px;
      height: 2px;
      background: #fff;
      border-radius: 2px;
      transition: 0.2s;
    }

    /* 移动端菜单 */
    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: 80px;
        left: 0;
        width: 100%;
        background: var(--bg-overlay);
        backdrop-filter: blur(20px);
        flex-direction: column;
        gap: 32px;
        padding: 40px;
        align-items: center;
        transform: translateX(100%);
        transition: transform 0.3s ease;
        border-bottom: 1px solid var(--border-subtle);
      }
      .nav-links.active {
        transform: translateX(0);
      }
      .menu-toggle {
        display: flex;
      }
      .btn-primary-small {
        display: none; /* 移动端CTAlogo旁隐藏，菜单内显示备用，但这里简化 */
      }
    }

    /* ----- 通用板块样式 ----- */
    section {
      padding: 100px 0;
    }

    @media (max-width: 768px) {
      section {
        padding: 70px 0;
      }
    }

    .section-title h2 {
      font-size: clamp(1.8rem, 4vw, 2.8rem);
      font-weight: 700;
      letter-spacing: -0.01em;
      margin-bottom: 12px;
      color: var(--text-on-dark);
    }
    .section-title .accent-line {
      display: inline-block;
      width: 60px;
      height: 3px;
      background: linear-gradient(135deg, var(--primary), var(--accent));
      margin-bottom: 24px;
    }
    .alt-bg-light {
      background-color: var(--bg-light-section);
      color: var(--text-on-light);
    }
    .alt-bg-light h2, .alt-bg-light h3 {
      color: #1E1B2E;
    }

    /* 按钮系统 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 14px 32px;
      border-radius: var(--radius-sm);
      font-weight: 700;
      transition: all 0.25s;
      cursor: pointer;
      border: none;
      font-family: var(--font-sans);
    }
    .btn-primary {
      background: var(--cta);
      color: #fff;
      box-shadow: 0 4px 12px rgba(255,107,53,0.25);
    }
    .btn-primary:hover {
      background: var(--cta-hover);
      box-shadow: 0 0 24px rgba(255,107,53,0.5);
      transform: translateY(-2px);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
    }
    .btn-outline:hover {
      background: rgba(124,58,237,0.1);
      border-color: var(--accent);
      color: var(--accent);
    }

    /* Hero 区域 */
    .hero {
      min-height: 90vh;
      display: flex;
      align-items: center;
      background: radial-gradient(circle at 30% 40%, #1a1035 0%, #0A0A0F 80%);
      position: relative;
      overflow: hidden;
    }
    .hero::before {
      content: "";
      position: absolute;
      inset: 0;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      opacity: 0.3;
      z-index: 0;
    }
    .hero-content {
      position: relative;
      z-index: 2;
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
      align-items: center;
    }
    .hero-text h1 {
      font-size: clamp(2.8rem, 6vw, 4.5rem);
      font-weight: 800;
      line-height: 1.12;
      color: #FFFFFF;
      margin-bottom: 18px;
    }
    .hero-text h1 .gradient-text {
      background: linear-gradient(135deg, #7C3AED 0%, #00F0FF 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      display: inline-block;
    }
    .hero-desc {
      font-size: 1.2rem;
      color: #9CA3AF;
      margin-bottom: 32px;
      max-width: 480px;
    }
    .hero-image img {
      width: 100%;
      border-radius: 24px;
      box-shadow: 0 20px 50px rgba(124,58,237,0.25);
    }
    @media (max-width: 768px) {
      .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
      }
      .hero-desc {
        margin-left: auto;
        margin-right: auto;
      }
    }

    /* 卡片通用 */
    .card {
      background: var(--bg-card);
      border-radius: var(--radius-md);
      padding: 32px;
      border: 1px solid var(--border-card);
      box-shadow: var(--shadow-card);
      transition: var(--transition);
      height: 100%;
    }
    .card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-5px);
      border-color: rgba(0,240,255,0.25);
    }

    /* 数值/优势数字 */
    .stat-number {
      font-family: var(--font-mono);
      font-weight: 800;
      font-size: 2.8rem;
      color: var(--accent);
      line-height: 1.1;
    }

    /* FAQ 问答 */
    .faq-item {
      border-bottom: 1px solid rgba(124,58,237,0.15);
      padding: 28px 0;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      cursor: pointer;
      color: #1E1B2E;
      font-size: 1.1rem;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: #4B4B5A;
      margin-top: 0;
    }
    .faq-item.active .faq-answer {
      margin-top: 12px;
      max-height: 180px;
    }
    .faq-icon {
      transition: transform 0.3s;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }

    /* 价格卡片 */
    .pricing-card {
      background: #fff;
      border-radius: 20px;
      padding: 36px 24px;
      border: 1px solid transparent;
      transition: 0.2s;
      text-align: center;
    }
    .pricing-card.featured {
      border: 2px solid #FF6B35;
      background: #FFFBF5;
      transform: scale(1.03);
      box-shadow: 0 20px 40px rgba(255,107,53,0.15);
      position: relative;
      z-index: 2;
    }
    .badge {
      background: #FF6B35;
      color: white;
      padding: 4px 16px;
      border-radius: 20px;
      font-size: 0.8rem;
      font-weight: 700;
      display: inline-block;
      margin-bottom: 12px;
    }

    @media (max-width: 768px) {
      .grid-3, .grid-2, .grid-4 {
        grid-template-columns: 1fr;
      }
    }