/* roulang page: index */
/* ----- 设计变量与基础重置 ----- */
    :root {
      --primary-purple: #7B2FF7;
      --accent-cyan: #00F0FF;
      --bg-deep: #0B0C10;
      --card-bg: rgba(20, 22, 28, 0.75);
      --text-light: #E0E0E0;
      --text-white: #FFFFFF;
      --success-green: #39FF14;
      --warning-orange: #FFB300;
      --border-glow: rgba(0, 240, 255, 0.15);
      --radius-card: 16px;
      --radius-btn: 50px;
      --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.4);
      --shadow-glow: 0 0 20px rgba(0, 240, 255, 0.25);
      --font-title: "PingFang SC", "Microsoft YaHei", "Inter", system-ui, sans-serif;
      --font-body: "Inter", "PingFang SC", system-ui, sans-serif;
      --font-mono: "Inter", "DIN Alternate", monospace;
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: var(--font-body);
      background-color: var(--bg-deep);
      color: var(--text-light);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s, background 0.2s;
    }

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: transparent;
    }

    /* 容器 */
    .container {
      width: 90%;
      max-width: 1280px;
      margin: 0 auto;
    }

    /* 板块通用 */
    section {
      padding: 80px 0;
      position: relative;
    }

    h2 {
      font-family: var(--font-title);
      font-weight: 800;
      font-size: 40px;
      color: var(--text-white);
      margin-bottom: 16px;
      letter-spacing: -0.5px;
    }

    .section-subhead {
      font-size: 1.1rem;
      color: var(--text-light);
      margin-bottom: 48px;
      max-width: 680px;
      line-height: 1.6;
    }

    /* ----- 导航 ----- */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: rgba(10, 11, 16, 0.88);
      backdrop-filter: blur(14px);
      -webkit-backdrop-filter: blur(14px);
      border-bottom: 1px solid rgba(0, 240, 255, 0.15);
      z-index: 999;
      display: flex;
      align-items: center;
    }

    .header-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 90%;
      max-width: 1280px;
      margin: 0 auto;
    }

    .logo {
      display: flex;
      align-items: center;
      font-family: var(--font-title);
      font-weight: 800;
      font-size: 1.8rem;
      color: var(--text-white);
      letter-spacing: -0.5px;
    }

    .logo-icon {
      margin-right: 10px;
      font-size: 2rem;
      color: var(--accent-cyan);
      filter: drop-shadow(0 0 8px rgba(0,240,255,0.6));
    }

    .nav-links {
      display: flex;
      gap: 32px;
      list-style: none;
    }

    .nav-links a {
      font-weight: 500;
      color: var(--text-light);
      position: relative;
      padding: 6px 0;
      font-size: 0.95rem;
    }

    .nav-links a::after {
      content: "";
      position: absolute;
      bottom: -2px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--accent-cyan);
      box-shadow: 0 0 8px var(--accent-cyan);
      transition: width 0.2s;
    }

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

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

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: transparent;
      border: none;
    }

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

    /* 移动端导航 */
    @media (max-width: 768px) {
      .hamburger {
        display: flex;
        z-index: 1001;
      }
      .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 70%;
        height: 100vh;
        background: rgba(8, 9, 13, 0.96);
        backdrop-filter: blur(20px);
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 32px;
        transition: right 0.35s ease;
        z-index: 1000;
      }
      .nav-links.active {
        right: 0;
      }
      .nav-links a {
        font-size: 1.6rem;
        font-weight: 600;
      }
    }

    /* ----- 按钮系统 ----- */
    .btn-primary {
      background: var(--accent-cyan);
      color: #0B0C10;
      font-weight: 700;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: all 0.25s;
      box-shadow: 0 4px 14px rgba(0,240,255,0.35);
      letter-spacing: 0.3px;
    }
    .btn-primary:hover {
      background: #33F5FF;
      box-shadow: 0 0 24px rgba(0,240,255,0.7);
      transform: scale(1.03);
    }

    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--accent-cyan);
      color: var(--accent-cyan);
      padding: 12px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: 0.25s;
    }
    .btn-outline:hover {
      background: rgba(0,240,255,0.08);
      box-shadow: 0 0 16px rgba(0,240,255,0.35);
    }

    /* ----- 首屏英雄 ----- */
    #hero {
      height: 100vh;
      display: flex;
      align-items: center;
      background: radial-gradient(circle at 30% 40%, rgba(123, 47, 247, 0.25) 0%, transparent 55%);
      position: relative;
      overflow: hidden;
    }
    .hero-bg {
      position: absolute;
      right: -10%;
      top: 10%;
      width: 55%;
      opacity: 0.25;
      pointer-events: none;
    }
    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 700px;
    }
    .hero-content h1 {
      font-family: var(--font-title);
      font-weight: 800;
      font-size: 58px;
      line-height: 1.15;
      background: linear-gradient(135deg, #B57BFF, var(--accent-cyan));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      text-shadow: 0 0 30px rgba(0,240,255,0.3);
      margin-bottom: 20px;
    }
    .hero-content p {
      font-size: 1.2rem;
      color: #ccc;
      margin-bottom: 32px;
      max-width: 540px;
    }

    @media (max-width: 768px) {
      .hero-content h1 {
        font-size: 38px;
      }
      .hero-bg {
        width: 90%;
        right: -30%;
        opacity: 0.18;
      }
    }

    /* 卡片栅格 */
    .card-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .card {
      background: var(--card-bg);
      backdrop-filter: blur(12px);
      border: 1px solid var(--border-glow);
      border-radius: var(--radius-card);
      padding: 32px 24px;
      box-shadow: var(--shadow-card);
      transition: 0.3s;
    }
    .card:hover {
      transform: translateY(-8px);
      box-shadow: 0 14px 36px rgba(0,0,0,0.6), 0 0 22px rgba(0,240,255,0.4);
      border-color: rgba(0,240,255,0.5);
    }
    .card-icon {
      font-size: 2.6rem;
      color: var(--accent-cyan);
      margin-bottom: 20px;
    }
    .card h3 {
      font-family: var(--font-title);
      font-weight: 700;
      font-size: 1.5rem;
      color: white;
      margin-bottom: 12px;
    }

    /* 数据块 */
    .data-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 30px;
      text-align: center;
    }
    .data-item .number {
      font-family: var(--font-mono);
      font-weight: 700;
      font-size: 52px;
      background: linear-gradient(to bottom, var(--accent-cyan), #7B2FF7);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }
    .data-label {
      color: #aaa;
      margin-top: 8px;
    }

    @media (max-width: 1024px) {
      .card-grid { grid-template-columns: repeat(2, 1fr); }
      .data-grid { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 640px) {
      .card-grid, .data-grid { grid-template-columns: 1fr; }
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid rgba(255,255,255,0.08);
      padding: 20px 0;
    }
    .faq-question {
      font-weight: 600;
      display: flex;
      align-items: center;
      gap: 16px;
      cursor: pointer;
      color: white;
      font-size: 1.1rem;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: 0.3s;
      color: #bbb;
      padding-left: 36px;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      margin-top: 16px;
    }

    /* 页脚 */
    .site-footer {
      background: #0A0B0F;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    @media (max-width: 768px) {
      .footer-grid { grid-template-columns: 1fr 1fr; }
      section { padding: 60px 0; }
    }