/* roulang page: index */
:root {
      --electric: #7B2FF7;
      --electric-deep: #5A1FCF;
      --compete: #FF6B35;
      --compete-light: #FF8150;
      --dark: #0C0C0F;
      --dark-side: #0A0A0D;
      --dark-card: rgba(255,255,255,0.04);
      --border-light: rgba(255,255,255,0.08);
      --text-main: #FFFFFF;
      --text-secondary: #B0B3BF;
      --text-muted: #6F7380;
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: 'PingFang SC', 'Microsoft YaHei', 'Inter', system-ui, -apple-system, sans-serif;
      background-color: var(--dark);
      color: var(--text-secondary);
      line-height: 1.75;
      font-size: 16px;
      display: flex;
      min-height: 100vh;
    }

    /* 左侧固定导航栏 */
    .app-shell {
      position: fixed;
      left: 0;
      top: 0;
      bottom: 0;
      width: 16rem; /* w-64 */
      background-color: var(--dark-side);
      border-right: 1px solid var(--border-light);
      display: flex;
      flex-direction: column;
      z-index: 50;
      padding: 2rem 1.5rem;
      transition: transform 0.3s ease;
    }

    .logo-text {
      font-size: 1.25rem;
      font-weight: 700;
      color: var(--text-main);
      letter-spacing: 0.5px;
    }

    .nav-menu {
      margin-top: 3rem;
      display: flex;
      flex-direction: column;
      gap: 1.5rem;
      flex: 1;
    }

    .nav-link {
      font-size: 0.875rem;
      color: var(--text-muted);
      text-decoration: none;
      padding-left: 1rem;
      position: relative;
      transition: color 0.2s;
      font-weight: 500;
      display: flex;
      align-items: center;
    }

    .nav-link:hover {
      color: var(--text-main);
    }

    .nav-link.active {
      color: var(--text-main);
    }

    .nav-link.active::before {
      content: '';
      position: absolute;
      left: 0;
      top: 50%;
      transform: translateY(-50%);
      width: 3px;
      height: 1.25rem;
      background-color: var(--electric);
      border-radius: 0 2px 2px 0;
    }

    .side-cta {
      background-color: var(--compete);
      color: white;
      text-align: center;
      padding: 0.75rem 1rem;
      border-radius: 9999px;
      font-weight: 600;
      font-size: 0.875rem;
      width: 80%;
      align-self: flex-start;
      transition: background-color 0.2s, transform 0.2s;
      text-decoration: none;
      display: inline-block;
    }

    .side-cta:hover {
      background-color: var(--compete-light);
      transform: scale(1.05);
    }

    /* 主内容区域 */
    .main-content {
      margin-left: 16rem;
      width: calc(100% - 16rem);
      position: relative;
    }

    /* 移动端导航 */
    .mobile-nav {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      right: 0;
      height: 3.5rem;
      background-color: var(--dark-side);
      border-bottom: 1px solid var(--border-light);
      z-index: 100;
      align-items: center;
      justify-content: space-between;
      padding: 0 1rem;
    }

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

    .hamburger span {
      display: block;
      width: 24px;
      height: 2px;
      background: white;
      border-radius: 2px;
    }

    .mobile-drawer {
      position: fixed;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
      background-color: rgba(10, 10, 13, 0.98);
      z-index: 200;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      transform: translateX(100%);
      transition: transform 0.3s ease;
    }

    .mobile-drawer.open {
      transform: translateX(0);
    }

    .drawer-close {
      position: absolute;
      top: 1.25rem;
      right: 1.5rem;
      background: none;
      border: none;
      color: white;
      font-size: 2rem;
      cursor: pointer;
    }

    /* 容器与排版 */
    .container-custom {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 2rem;
    }

    section {
      padding-top: 6rem;
      padding-bottom: 6rem;
    }

    @media (min-width: 769px) {
      section {
        padding-top: 8rem;
        padding-bottom: 8rem;
      }
    }

    h1 {
      font-size: 3.5rem;
      font-weight: 700;
      line-height: 1.1;
      color: var(--text-main);
    }

    h2 {
      font-size: 2.25rem;
      font-weight: 600;
      line-height: 1.2;
      color: var(--text-main);
      margin-bottom: 3rem;
    }

    h3 {
      font-size: 1.25rem;
      font-weight: 600;
      line-height: 1.4;
      color: var(--text-main);
    }

    .card {
      background-color: var(--dark-card);
      border: 1px solid var(--border-light);
      border-radius: 12px;
      padding: 2rem;
      transition: transform 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94), box-shadow 0.3s;
    }

    .card:hover {
      transform: translateY(-4px);
      box-shadow: 0 0 20px rgba(123, 47, 247, 0.15);
    }

    .btn-primary {
      background-color: var(--compete);
      color: white;
      font-weight: 600;
      padding: 0.75rem 2rem;
      border-radius: 9999px;
      display: inline-block;
      transition: background-color 0.2s, transform 0.2s;
      text-decoration: none;
      border: none;
      cursor: pointer;
      font-size: 1rem;
    }

    .btn-primary:hover {
      background-color: var(--compete-light);
      transform: scale(1.05);
    }

    .text-gradient {
      background: linear-gradient(135deg, #7B2FF7 0%, #A855F7 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }

    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 1.5rem 0;
    }

    .faq-question {
      font-size: 1.125rem;
      font-weight: 500;
      color: var(--text-main);
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      background: none;
      border: none;
      width: 100%;
      text-align: left;
      padding: 0;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease;
      color: var(--text-secondary);
      font-size: 0.9375rem;
      padding-right: 2rem;
      margin-top: 0;
    }

    .faq-item.open .faq-answer {
      max-height: 10rem;
      margin-top: 1rem;
    }

    .faq-arrow {
      transition: transform 0.35s ease;
      font-size: 1.25rem;
      color: var(--text-muted);
    }

    .faq-item.open .faq-arrow {
      transform: rotate(180deg);
      color: var(--electric);
    }

    /* 响应式 */
    @media (max-width: 768px) {
      .app-shell {
        display: none;
      }
      .main-content {
        margin-left: 0;
        width: 100%;
      }
      .mobile-nav {
        display: flex;
      }
      .container-custom {
        padding: 0 1.25rem;
      }
      h1 {
        font-size: 2.25rem;
      }
      h2 {
        font-size: 1.75rem;
        margin-bottom: 2rem;
      }
      .text-gradient {
        font-size: 2rem;
      }
      section {
        padding-top: 4rem;
        padding-bottom: 4rem;
      }
      .data-number {
        font-size: 2rem;
      }
      .offset-grid {
        grid-template-columns: 1fr;
      }
    }

    .hero-bg {
      background: radial-gradient(circle at 30% 40%, rgba(123,47,247,0.15) 0%, transparent 60%),
                  repeating-linear-gradient(0deg, rgba(255,255,255,0.02) 0px, rgba(255,255,255,0.02) 1px, transparent 1px, transparent 40px),
                  repeating-linear-gradient(90deg, rgba(255,255,255,0.02) 0px, rgba(255,255,255,0.02) 1px, transparent 1px, transparent 40px);
    }