/* roulang page: index */
/* 设计变量 & reset 完整体系 */
    :root {
      --primary-deep: #4B0E6B;
      --primary-purple: #8A2BE2;
      --accent-cyan: #00E5FF;
      --amber-gold: #FFB300;
      --bg-deep: #0D0D1A;
      --bg-card: rgba(26, 26, 46, 0.8);
      --border-light: rgba(255, 255, 255, 0.06);
      --text-primary: #FFFFFF;
      --text-secondary: #B0B0C0;
      --shadow-card: 0 10px 30px rgba(0, 0, 0, 0.5);
      --shadow-hover: 0 15px 40px rgba(138, 43, 226, 0.45);
      --radius-xl: 24px;
      --radius-lg: 16px;
      --radius-md: 12px;
      --radius-btn: 8px;
      --font-numbers: 'Inter', 'Roboto', sans-serif;
      --font-body: 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', sans-serif;
      --transition-all: all 0.25s ease-out;
    }

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

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

    body {
      font-family: var(--font-body);
      background-color: var(--bg-deep);
      color: var(--text-primary);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
    }

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

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

    ul, ol {
      list-style: none;
    }

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      transition: var(--transition-all);
      border: none;
      background: transparent;
    }

    /* container & layout utilities */
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }

    section {
      padding: 100px 0;
    }

    .section-header {
      text-align: center;
      margin-bottom: 60px;
    }

    h2 {
      font-size: clamp(32px, 5vw, 44px);
      font-weight: 700;
      color: white;
      letter-spacing: -0.3px;
    }

    .accent-text {
      color: var(--accent-cyan);
      text-shadow: 0 0 12px rgba(0, 229, 255, 0.25);
    }

    .secondary-text {
      color: var(--text-secondary);
      font-size: 1.1rem;
      margin-top: 1rem;
    }

    /* :) base buttons */
    .btn-primary {
      background: linear-gradient(135deg, #8A2BE2, #4B0E6B);
      color: white;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 1rem;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      border: none;
      box-shadow: 0 4px 14px rgba(138, 43, 226, 0.4);
      letter-spacing: 0.5px;
    }

    .btn-primary:hover {
      background: linear-gradient(135deg, #9b3cf0, #5e1d88);
      box-shadow: 0 0 22px rgba(138, 43, 226, 0.75);
      transform: translateY(-2px);
    }

    .btn-outline {
      background: transparent;
      border: 1px solid var(--accent-cyan);
      color: var(--accent-cyan);
      padding: 14px 34px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 1rem;
      backdrop-filter: blur(4px);
    }

    .btn-outline:hover {
      background: rgba(0, 229, 255, 0.12);
      border-color: #00f0ff;
      box-shadow: 0 0 18px rgba(0, 229, 255, 0.35);
    }

    /* ---------- 导航 NAVIGATION (沉浸式) ---------- */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: rgba(13, 13, 26, 0.82);
      backdrop-filter: blur(14px);
      border-bottom: 1px solid rgba(138, 43, 226, 0.4);
      padding: 15px 0;
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: 1300px;
      margin: 0 auto;
      padding: 0 20px;
    }

    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 1.6rem;
      background: linear-gradient(to right, #c084fc, #00e5ff);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      letter-spacing: 1px;
    }

    .nav-menu {
      display: flex;
      gap: 28px;
    }

    .nav-menu a {
      font-size: 0.98rem;
      font-weight: 500;
      color: var(--text-secondary);
      padding: 6px 0;
      position: relative;
    }

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

    .nav-menu a::after {
      content: '';
      position: absolute;
      bottom: -3px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--accent-cyan);
      transition: 0.25s;
    }

    .nav-menu a:hover::after,
    .nav-menu a.active::after {
      width: 100%;
    }

    .mobile-toggle {
      display: none;
      background: none;
      border: none;
      color: white;
      font-size: 2rem;
    }

    @media (max-width: 768px) {
      .nav-menu {
        position: absolute;
        top: 70px;
        left: 0;
        width: 100%;
        background: rgba(10, 10, 20, 0.95);
        backdrop-filter: blur(20px);
        flex-direction: column;
        align-items: center;
        padding: 32px;
        gap: 24px;
        display: none;
        border-radius: 0 0 16px 16px;
      }
      .nav-menu.active-mobile {
        display: flex;
      }
      .mobile-toggle {
        display: block;
      }
    }

    /* ---------- HERO ---------- */
    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      background-blend-mode: overlay;
      background-color: rgba(13, 13, 26, 0.75);
      position: relative;
    }
    .hero-content {
      max-width: 700px;
      margin-top: 30px;
    }
    h1 {
      font-size: clamp(48px, 7vw, 64px);
      font-weight: 800;
      background: linear-gradient(180deg, #fff 20%, #b68eff);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      letter-spacing: -1px;
      line-height: 1.2;
      margin-bottom: 1.2rem;
    }
    .hero p {
      font-size: 1.2rem;
      color: #ccccdd;
      margin-bottom: 2.4rem;
    }
    .btn-group {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }

    /* ---------- 优势区块 不对称网格 ---------- */
    .advantages-grid {
      display: grid;
      grid-template-columns: 1.2fr 0.8fr 1fr;
      gap: 30px;
    }
    @media (max-width: 900px) {
      .advantages-grid {
        grid-template-columns: 1fr;
      }
    }
    .adv-card {
      background: var(--bg-card);
      border-radius: var(--radius-lg);
      padding: 32px 24px;
      border: 1px solid var(--border-light);
      transition: 0.3s;
    }
    .adv-card:hover {
      border-color: rgba(138,43,226,0.4);
      box-shadow: var(--shadow-hover);
    }

    /* 数据墙/徽章 */
    .stats-wall {
      background: #0A0A14;
      display: flex;
      justify-content: space-around;
      flex-wrap: wrap;
      gap: 30px;
    }
    .stat-item {
      text-align: center;
    }
    .stat-num {
      font-size: 56px;
      font-weight: 800;
      font-family: var(--font-numbers);
      color: var(--amber-gold);
      text-shadow: 0 0 20px rgba(255,179,0,0.55);
    }

    /* 案例卡片 */
    .case-grid {
      display: flex;
      gap: 28px;
      overflow-x: auto;
      padding-bottom: 12px;
    }
    .case-card {
      min-width: 300px;
      background: var(--bg-card);
      border-radius: 16px;
      border: 1px solid var(--border-light);
    }
    .case-card img {
      border-radius: 16px 16px 0 0;
      height: 180px;
      object-fit: cover;
    }

    /* faq 手风琴 base */
    .faq-item {
      background: #111126;
      margin-bottom: 14px;
      border-radius: 12px;
      border-left: 4px solid var(--accent-cyan);
    }

    /* 微布局之类的完整显示完整 */
    footer {
      background: #0b0b16;
      border-top: 1px solid rgba(138,43,226,0.4);
    }

    .responsive-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px,1fr)); gap: 34px; }

    @media (max-width: 520px) {
      .btn-group { flex-direction: column; align-items: flex-start; }
    }