/* roulang page: index */
/* ----- 设计变量与重置 ----- */
    :root {
      --primary: #0AE08E;
      --primary-glow: rgba(10, 224, 142, 0.4);
      --secondary-bg: #2D0B4E;
      --accent: #FF2E63;
      --bg-deep: #0B0C10;
      --bg-section: #0F1117;
      --card-bg: rgba(255, 255, 255, 0.04);
      --card-border: rgba(10, 224, 142, 0.15);
      --text-white: #FFFFFF;
      --text-body: #B0B8C1;
      --text-muted: #6B7280;
      --radius-lg: 16px;
      --radius-full: 50px;
      --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.4);
      --shadow-hover: 0 16px 48px rgba(10, 224, 142, 0.15);
      --nav-width: 72px;
      --nav-tablet: 64px;
      --header-mobile: 48px;
      --transition: 0.25s ease;
      --font-cn: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --font-en: "Inter", "DIN Alternate", sans-serif;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }
    body {
      font-family: var(--font-cn);
      background-color: var(--bg-deep);
      color: var(--text-body);
      line-height: 1.7;
      min-height: 100vh;
      display: flex;
      flex-direction: column;
      overflow-x: hidden;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }
    button, input {
      font-family: inherit;
      outline: none;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    /* ----- 左侧导航 (桌面) ----- */
    .side-nav {
      position: fixed;
      left: 0;
      top: 0;
      width: var(--nav-width);
      height: 100vh;
      background: #0F1117;
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 24px 0;
      z-index: 1000;
      border-right: 1px solid rgba(255,255,255,0.06);
      transition: width var(--transition);
    }
    .logo-area {
      display: flex;
      flex-direction: column;
      align-items: center;
      margin-bottom: 48px;
      color: var(--primary);
      font-weight: 700;
      letter-spacing: 1px;
    }
    .logo-icon {
      width: 36px;
      height: 36px;
      background: linear-gradient(135deg, #0AE08E, #0ccf7a);
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: #0B0C10;
      font-size: 22px;
      margin-bottom: 6px;
      box-shadow: 0 0 14px var(--primary-glow);
    }
    .logo-text {
      writing-mode: vertical-lr;
      font-size: 14px;
      font-weight: 700;
      color: var(--text-white);
      letter-spacing: 2px;
    }
    .nav-menu {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 28px;
      width: 100%;
      align-items: center;
      flex: 1;
    }
    .nav-item {
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      width: 100%;
      padding: 6px 0;
      position: relative;
      color: var(--text-muted);
      font-size: 12px;
      font-weight: 500;
      transition: color var(--transition);
    }
    .nav-item i {
      font-size: 22px;
      margin-bottom: 4px;
      transition: text-shadow var(--transition);
    }
    .nav-item.active {
      color: var(--primary);
    }
    .nav-item.active::before {
      content: '';
      position: absolute;
      left: 0;
      top: 8px;
      bottom: 8px;
      width: 3px;
      background: var(--primary);
      border-radius: 0 4px 4px 0;
      box-shadow: 0 0 12px var(--primary);
    }
    .nav-item:hover {
      color: var(--primary);
      text-shadow: 0 0 8px var(--primary-glow);
    }
    /* 移动端顶部导航 */
    .mobile-header {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--header-mobile);
      background: rgba(15, 17, 23, 0.9);
      backdrop-filter: blur(16px);
      z-index: 999;
      align-items: center;
      justify-content: space-between;
      padding: 0 20px;
      border-bottom: 1px solid rgba(255,255,255,0.06);
    }
    .hamburger {
      font-size: 24px;
      color: var(--text-white);
      background: transparent;
      border: none;
    }
    .mobile-logo {
      font-weight: 700;
      color: var(--primary);
      font-size: 18px;
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .drawer {
      position: fixed;
      top: 0;
      left: -280px;
      width: 260px;
      height: 100vh;
      background: #0F1117;
      backdrop-filter: blur(20px);
      padding: 32px 20px;
      transition: left 0.3s ease;
      z-index: 1001;
      display: flex;
      flex-direction: column;
      gap: 28px;
    }
    .drawer.open {
      left: 0;
    }
    .drawer a {
      color: var(--text-body);
      font-size: 18px;
      display: flex;
      align-items: center;
      gap: 12px;
    }
    .drawer .active {
      color: var(--primary);
    }
    /* 主内容区偏移 */
    .main-content {
      margin-left: var(--nav-width);
      width: calc(100% - var(--nav-width));
      transition: margin-left var(--transition), width var(--transition);
    }
    /* ----- 板块通用 ----- */
    section {
      padding: 100px 0;
      position: relative;
    }
    .section-title {
      font-size: 32px;
      font-weight: 700;
      color: var(--text-white);
      margin-bottom: 16px;
      letter-spacing: -0.3px;
    }
    .section-sub {
      color: var(--text-body);
      font-size: 18px;
      margin-bottom: 48px;
      max-width: 600px;
    }
    .grid {
      display: grid;
      gap: 24px;
    }
    .grid-3 {
      grid-template-columns: repeat(3, 1fr);
    }
    .grid-4 {
      grid-template-columns: repeat(4, 1fr);
    }
    /* 卡片 */
    .glass-card {
      background: var(--card-bg);
      backdrop-filter: blur(16px);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-lg);
      padding: 28px;
      box-shadow: var(--shadow-card);
      transition: all 0.3s ease;
    }
    .glass-card:hover {
      transform: translateY(-4px);
      border-color: rgba(10,224,142,0.4);
      box-shadow: var(--shadow-hover);
    }
    .btn-primary {
      background: var(--primary);
      color: #0B0C10;
      border-radius: var(--radius-full);
      padding: 14px 36px;
      font-weight: 700;
      font-size: 16px;
      letter-spacing: 0.5px;
      border: none;
      box-shadow: 0 0 24px var(--primary-glow);
      cursor: pointer;
      transition: 0.3s;
      display: inline-block;
    }
    .btn-primary:hover {
      transform: scale(1.05);
      box-shadow: 0 0 40px var(--primary-glow);
    }
    .btn-outline {
      border: 1px solid var(--primary);
      color: var(--primary);
      background: transparent;
      border-radius: var(--radius-full);
      padding: 12px 32px;
      font-weight: 600;
      transition: 0.3s;
    }
    .btn-outline:hover {
      background: rgba(10,224,142,0.08);
    }
    .text-link {
      color: var(--primary);
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      border-bottom: 1px solid transparent;
      transition: 0.2s;
    }
    .text-link:hover {
      border-bottom-color: var(--primary);
    }
    /* Hero */
    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: radial-gradient(circle at 20% 40%, #2D0B4E 0%, #0B0C10 80%);
      position: relative;
      overflow: hidden;
    }
    .speed-lines {
      position: absolute;
      width: 100%;
      height: 100%;
      background: repeating-linear-gradient(45deg, rgba(10,224,142,0.03) 0px, rgba(10,224,142,0.03) 2px, transparent 2px, transparent 8px);
      pointer-events: none;
    }
    .hero-content {
      max-width: 700px;
    }
    .hero h1 {
      font-size: 48px;
      font-weight: 700;
      color: white;
      line-height: 1.2;
      letter-spacing: -0.5px;
      margin-bottom: 20px;
    }
    .highlight {
      color: var(--primary);
      text-shadow: 0 0 12px var(--primary-glow);
    }
    /* 数据统计 */
    .stat-number {
      font-family: var(--font-en);
      font-size: 48px;
      font-weight: 700;
      color: var(--primary);
    }
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid rgba(255,255,255,0.06);
      padding: 18px 0;
      cursor: pointer;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      font-weight: 600;
      color: white;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-body);
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-top: 12px;
    }
    /* 响应式 */
    @media (max-width: 1279px) {
      .side-nav { width: var(--nav-tablet); }
      .main-content { margin-left: var(--nav-tablet); width: calc(100% - var(--nav-tablet)); }
      .logo-text { font-size: 12px; }
    }
    @media (max-width: 1023px) {
      .side-nav { display: none; }
      .mobile-header { display: flex; }
      .main-content { margin-left: 0; width: 100%; }
      .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
      .hero h1 { font-size: 40px; }
    }
    @media (max-width: 767px) {
      .grid-3, .grid-4 { grid-template-columns: 1fr; }
      .hero h1 { font-size: 36px; }
      .section-title { font-size: 24px; }
      .glass-card { border-radius: 12px; }
    }