/* roulang page: index */
:root {
      --color-bg-primary: #0B0D21;
      --color-bg-secondary: #080A1A;
      --color-accent-purple: #6C5CE7;
      --color-accent-cyan: #00D2FF;
      --color-accent-gold: #FFD700;
      --color-text-primary: #E8E8F0;
      --color-text-secondary: #9A9AB0;
      --color-text-muted: #6A6A80;
      --glass-bg: rgba(255, 255, 255, 0.03);
      --glass-border: rgba(108, 92, 231, 0.25);
      --glass-border-hover: rgba(0, 210, 255, 0.45);
      --card-shadow: 0 8px 32px rgba(0, 0, 0, 0.4), inset 0 1px 0 rgba(255, 255, 255, 0.05);
      --card-shadow-hover: 0 12px 36px rgba(0, 0, 0, 0.5), 0 0 24px rgba(0, 210, 255, 0.2);
      --radius-card: 20px;
      --radius-btn: 12px;
      --radius-input: 10px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
      --font-number: "Inter", "SF Pro Display", system-ui, sans-serif;
      --transition-smooth: 0.35s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    }

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

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

    body {
      font-family: var(--font-sans);
      background-color: var(--color-bg-primary);
      color: var(--color-text-primary);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
      display: flex;
      min-height: 100vh;
    }

    /* 左侧竖向导航 (桌面端) */
    .side-nav {
      position: fixed;
      left: 0;
      top: 0;
      width: 240px;
      height: 100vh;
      background: rgba(11, 13, 33, 0.85);
      backdrop-filter: blur(30px);
      -webkit-backdrop-filter: blur(30px);
      border-right: 1px solid rgba(108, 92, 231, 0.15);
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 40px 0 30px;
      z-index: 100;
      transition: transform 0.3s ease;
    }

    .logo-area {
      margin-bottom: 60px;
      text-align: center;
    }
    .logo-text {
      font-size: 28px;
      font-weight: 700;
      letter-spacing: 2px;
      background: linear-gradient(135deg, #E8E8F0 0%, #00D2FF 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .logo-sub {
      font-size: 12px;
      color: var(--color-text-secondary);
      letter-spacing: 2px;
      margin-top: 4px;
    }

    .nav-links {
      display: flex;
      flex-direction: column;
      gap: 18px;
      width: 100%;
      padding: 0 30px;
      flex: 1;
    }
    .nav-link {
      color: var(--color-text-secondary);
      text-decoration: none;
      font-size: 16px;
      font-weight: 500;
      padding: 8px 16px;
      border-radius: 8px;
      position: relative;
      transition: color 0.2s, background 0.2s;
      display: flex;
      align-items: center;
    }
    .nav-link::before {
      content: '';
      position: absolute;
      left: 0;
      top: 50%;
      transform: translateY(-50%);
      width: 3px;
      height: 0;
      background: var(--color-accent-cyan);
      border-radius: 0 4px 4px 0;
      transition: height 0.25s ease;
    }
    .nav-link:hover {
      color: var(--color-text-primary);
      background: rgba(255,255,255,0.03);
    }
    .nav-link:hover::before {
      height: 60%;
    }
    .nav-cta {
      margin-top: 20px;
      width: 80%;
      text-align: center;
    }

    /* 右侧主内容区 */
    .main-content {
      margin-left: 240px;
      flex: 1;
      width: calc(100% - 240px);
    }

    /* 移动端顶部导航 */
    .mobile-nav {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 56px;
      background: rgba(11, 13, 33, 0.9);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-bottom: 1px solid rgba(108, 92, 231, 0.2);
      z-index: 110;
      align-items: center;
      justify-content: space-between;
      padding: 0 20px;
    }
    .mobile-logo {
      font-size: 22px;
      font-weight: 700;
      background: linear-gradient(135deg, #E8E8F0, #00D2FF);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }
    #menu-toggle {
      display: none;
    }
    .hamburger {
      display: flex;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
    }
    .hamburger span {
      width: 25px;
      height: 2px;
      background: var(--color-text-primary);
      transition: 0.3s;
    }
    .mobile-menu-overlay {
      position: fixed;
      top: 56px;
      left: 0;
      width: 100%;
      height: calc(100vh - 56px);
      background: rgba(8, 10, 26, 0.98);
      backdrop-filter: blur(20px);
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 30px;
      transform: translateX(100%);
      transition: transform 0.3s ease;
      z-index: 105;
    }
    #menu-toggle:checked ~ .mobile-menu-overlay {
      transform: translateX(0);
    }
    .mobile-link {
      font-size: 22px;
      color: var(--color-text-secondary);
      text-decoration: none;
    }

    /* 通用容器 */
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 40px;
    }

    section {
      padding: 100px 0;
    }

    h1, h2, h3 {
      font-weight: 600;
      letter-spacing: -0.02em;
    }

    /* 背景星场效果 */
    .star-bg {
      position: relative;
    }
    .star-bg::before {
      content: '';
      position: absolute;
      inset: 0;
      background: radial-gradient(circle at 30% 20%, rgba(108,92,231,0.08) 0%, transparent 50%);
      pointer-events: none;
    }

    /* Hero */
    .hero {
      height: 100vh;
      display: flex;
      align-items: center;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      position: relative;
    }
    .hero::after {
      content: '';
      position: absolute;
      inset: 0;
      background: radial-gradient(ellipse at 70% 40%, rgba(11,13,33,0.4) 0%, #0B0D21 90%);
    }
    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 700px;
    }
    .hero h1 {
      font-size: 52px;
      font-weight: 700;
      color: #E8E8F0;
      text-shadow: 0 0 20px rgba(0,210,255,0.3);
      margin-bottom: 24px;
    }
    .hero-sub {
      font-size: 20px;
      color: var(--color-text-secondary);
      margin-bottom: 40px;
    }
    .btn-group {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: linear-gradient(135deg, #6C5CE7, #00D2FF);
      border: none;
      color: white;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      box-shadow: 0 4px 20px rgba(108,92,231,0.4), 0 0 40px rgba(0,210,255,0.2);
      cursor: pointer;
      transition: var(--transition-smooth);
      text-decoration: none;
      display: inline-block;
    }
    .btn-primary:hover {
      box-shadow: 0 6px 28px rgba(108,92,231,0.6), 0 0 56px rgba(0,210,255,0.35);
      transform: translateY(-2px) scale(1.02);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid rgba(108,92,231,0.5);
      color: var(--color-text-primary);
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      cursor: pointer;
      transition: var(--transition-smooth);
      text-decoration: none;
    }
    .btn-outline:hover {
      border-color: #00D2FF;
      background: rgba(0,210,255,0.08);
      box-shadow: 0 0 20px rgba(0,210,255,0.15);
    }

    /* 卡片 */
    .glass-card {
      background: var(--glass-bg);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border: 1px solid var(--glass-border);
      border-radius: var(--radius-card);
      box-shadow: var(--card-shadow);
      padding: 32px;
      transition: var(--transition-smooth);
    }
    .glass-card:hover {
      border-color: var(--glass-border-hover);
      box-shadow: var(--card-shadow-hover);
      transform: translateY(-4px);
    }

    .grid-2 { display: grid; grid-template-columns: repeat(2,1fr); gap: 32px; }
    .grid-3 { display: grid; grid-template-columns: repeat(3,1fr); gap: 32px; }
    .grid-4 { display: grid; grid-template-columns: repeat(4,1fr); gap: 24px; }

    .section-title {
      font-size: 38px;
      margin-bottom: 16px;
    }
    .section-desc {
      color: var(--color-text-secondary);
      font-size: 18px;
      margin-bottom: 50px;
    }

    .card-img {
      width: 100%;
      height: 180px;
      object-fit: cover;
      border-radius: 12px;
      margin-bottom: 20px;
      background: #1a1c3a;
    }

    .metric-number {
      font-family: var(--font-number);
      font-size: 42px;
      font-weight: 800;
      background: linear-gradient(to right, #E8E8F0, #00D2FF);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      text-shadow: 0 0 15px rgba(0,210,255,0.5);
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid rgba(108,92,231,0.2);
      padding: 20px 0;
    }
    .faq-question {
      font-size: 20px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--color-text-secondary);
    }

    /* 页脚 */
    footer {
      background: #080A1A;
      padding: 60px 0 30px;
      border-top: 1px solid rgba(108,92,231,0.3);
    }

    @media (max-width: 1024px) {
      .side-nav { display: none; }
      .mobile-nav { display: flex; }
      .main-content { margin-left: 0; width: 100%; }
      .container { padding: 0 24px; }
      .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
      .hero h1 { font-size: 36px; }
    }