/* roulang page: index */
:root {
      --primary: #B026FF;
      --primary-strong: #8A1FCC;
      --accent: #00F0FF;
      --bg-deep: #0A0B10;
      --bg-card: rgba(20, 22, 36, 0.7);
      --border-glass: rgba(255, 255, 255, 0.12);
      --text-main: #F0F2FF;
      --text-muted: #9CA3AF;
      --radius-card: 1rem;
      --radius-btn: 0.5rem;
      --shadow-glow: 0 8px 32px rgba(176, 38, 255, 0.35);
      --shadow-cyan: 0 0 24px rgba(0, 240, 255, 0.5);
      --font-display: 'Orbitron', 'PingFang SC', 'Microsoft YaHei', sans-serif;
      --font-body: 'Inter', 'PingFang SC', 'Microsoft YaHei', sans-serif;
      --nav-width: 80px;
    }

    * {
      box-sizing: border-box;
    }

    body {
      margin: 0;
      font-family: var(--font-body);
      background-color: var(--bg-deep);
      color: var(--text-main);
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
      display: flex;
      min-height: 100vh;
    }

    /* 背景网格纹理 */
    body::before {
      content: "";
      position: fixed;
      top: 0; left: 0; width: 100%; height: 100%;
      background-image: 
        linear-gradient(rgba(176, 38, 255, 0.06) 1px, transparent 1px),
        linear-gradient(90deg, rgba(176, 38, 255, 0.06) 1px, transparent 1px);
      background-size: 48px 48px;
      pointer-events: none;
      z-index: 0;
    }

    a {
      color: var(--accent);
      text-decoration: none;
      transition: color 0.2s;
    }
    a:hover {
      color: var(--primary);
    }
    img {
      max-width: 100%;
      display: block;
    }
    button {
      font-family: inherit;
      cursor: pointer;
      border: none;
      background: none;
    }

    /* 左侧导航栏 (App Shell) */
    .app-nav {
      position: fixed;
      top: 0; left: 0;
      width: var(--nav-width);
      height: 100vh;
      background-color: rgba(10, 11, 16, 0.9);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-right: 1px solid var(--border-glass);
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 1.5rem 0;
      z-index: 50;
      box-shadow: 4px 0 20px rgba(0,0,0,0.6);
    }
    .nav-logo {
      font-family: var(--font-display);
      font-weight: 900;
      font-size: 1.6rem;
      color: var(--primary);
      text-shadow: 0 0 14px var(--primary);
      margin-bottom: 2.5rem;
      letter-spacing: 1px;
      display: flex;
      flex-direction: column;
      align-items: center;
      line-height: 1.2;
    }
    .nav-logo span {
      font-size: 0.65rem;
      font-weight: 600;
      color: var(--accent);
      text-shadow: 0 0 8px var(--accent);
      margin-top: 2px;
    }
    .nav-menu {
      display: flex;
      flex-direction: column;
      gap: 1.8rem;
      align-items: center;
      flex: 1;
    }
    .nav-item {
      color: #9CA3AF;
      font-size: 1.3rem;
      transition: all 0.25s;
      position: relative;
      display: flex;
      align-items: center;
      justify-content: center;
      width: 44px;
      height: 44px;
      border-radius: 12px;
    }
    .nav-item:hover {
      color: var(--accent);
      text-shadow: 0 0 16px var(--accent);
      background: rgba(0,240,255,0.08);
      transform: scale(1.08);
    }
    .nav-item.active {
      color: var(--accent);
      background: rgba(176,38,255,0.15);
      box-shadow: 0 0 14px rgba(176,38,255,0.5);
    }

    /* 主内容区域右移 */
    .main-content {
      margin-left: var(--nav-width);
      flex: 1;
      position: relative;
      z-index: 1;
      max-width: 100%;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 2rem;
    }

    /* 玻璃拟态卡片 */
    .glass-card {
      background: var(--bg-card);
      backdrop-filter: blur(16px);
      -webkit-backdrop-filter: blur(16px);
      border: 1px solid var(--border-glass);
      border-radius: var(--radius-card);
      box-shadow: 0 20px 40px rgba(0,0,0,0.5);
    }
    .glass-card:hover {
      border-color: rgba(176,38,255,0.4);
      box-shadow: var(--shadow-glow);
    }

    /* 按钮 */
    .btn-primary {
      background: linear-gradient(135deg, #B026FF, #00F0FF);
      color: white;
      font-weight: 700;
      padding: 0.9rem 2.2rem;
      border-radius: var(--radius-btn);
      box-shadow: 0 6px 20px rgba(176,38,255,0.45);
      transition: all 0.3s;
      display: inline-flex;
      align-items: center;
      gap: 0.5rem;
      letter-spacing: 0.5px;
      border: none;
      font-size: 1rem;
    }
    .btn-primary:hover {
      transform: scale(1.05);
      box-shadow: 0 10px 28px rgba(0,240,255,0.7);
      filter: brightness(1.1);
    }
    .btn-ghost {
      background: transparent;
      border: 2px solid var(--accent);
      color: var(--accent);
      font-weight: 700;
      padding: 0.85rem 2.2rem;
      border-radius: var(--radius-btn);
      transition: all 0.3s;
      display: inline-flex;
      align-items: center;
      gap: 0.5rem;
      font-size: 1rem;
    }
    .btn-ghost:hover {
      background: rgba(0,240,255,0.1);
      box-shadow: 0 0 22px rgba(0,240,255,0.5);
      transform: scale(1.03);
      color: white;
    }

    /* Section 标题 */
    .section-title {
      font-family: var(--font-display);
      font-size: 2.4rem;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 2px;
      background: linear-gradient(to right, #B026FF, #00F0FF);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }

    /* 汉堡菜单 (移动端) */
    .mobile-nav-toggle {
      display: none;
    }

    @media (max-width: 768px) {
      body {
        flex-direction: column;
      }
      .app-nav {
        position: fixed;
        top: 0; left: 0; right: 0;
        width: 100%;
        height: auto;
        flex-direction: row;
        justify-content: space-between;
        padding: 0.8rem 1.5rem;
        backdrop-filter: blur(20px);
        z-index: 60;
        border-right: none;
        border-bottom: 1px solid var(--border-glass);
      }
      .nav-menu {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        width: 100%;
        background: rgba(10,11,16,0.95);
        backdrop-filter: blur(30px);
        flex-direction: column;
        align-items: center;
        padding: 1.5rem 0;
        gap: 1.2rem;
        border-bottom: 1px solid var(--border-glass);
      }
      .nav-menu.open {
        display: flex;
      }
      .mobile-nav-toggle {
        display: block;
        font-size: 1.8rem;
        color: var(--accent);
      }
      .main-content {
        margin-left: 0;
        margin-top: 70px;
      }
      .nav-logo {
        margin-bottom: 0;
        flex-direction: row;
        gap: 0.4rem;
        font-size: 1.4rem;
      }
    }

    /* 瀑布流简易实现 */
    .masonry-grid {
      column-count: 3;
      column-gap: 1.5rem;
    }
    .masonry-item {
      break-inside: avoid;
      margin-bottom: 1.5rem;
    }
    @media (max-width: 768px) {
      .masonry-grid {
        column-count: 2;
      }
    }
    @media (max-width: 520px) {
      .masonry-grid {
        column-count: 1;
      }
    }

    /* FAQ 手风琴 */
    .faq-item {
      border: 1px solid var(--border-glass);
      border-radius: 12px;
      margin-bottom: 1rem;
      background: rgba(20,22,36,0.5);
      backdrop-filter: blur(6px);
      transition: all 0.3s;
    }
    .faq-item.active {
      border-color: var(--accent);
      background: rgba(0,240,255,0.05);
      box-shadow: 0 0 18px rgba(0,240,255,0.3);
    }
    .faq-question {
      padding: 1.2rem 1.5rem;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      padding: 0 1.5rem;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 1.2rem;
    }