/* roulang page: index */
:root {
      --primary-purple: #A855F7;
      --neon-cyan: #22D3EE;
      --deep-black: #0B0B0F;
      --card-bg: #1A1A2E;
      --light-purple: #C084FC;
      --warning-orange: #F97316;
      --text-white: #FFFFFF;
      --text-gray: #A1A1AA;
      --text-muted: #71717A;
      --border-subtle: rgba(168, 85, 247, 0.15);
      --border-glow: rgba(168, 85, 247, 0.4);
      --shadow-card: 0 0 0 1px rgba(168, 85, 247, 0.15);
      --shadow-hover: 0 12px 32px rgba(168, 85, 247, 0.25);
      --gradient-main: linear-gradient(135deg, #22D3EE 0%, #A855F7 100%);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
    }

    * {
      box-sizing: border-box;
    }

    body {
      margin: 0;
      font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", "Inter", sans-serif;
      background-color: var(--deep-black);
      color: var(--text-gray);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }

    h1, h2, h3, h4 {
      margin: 0;
      line-height: 1.2;
    }

    h1 {
      font-size: clamp(2.5rem, 8vw, 4rem);
      font-weight: 800;
      letter-spacing: -0.02em;
      background: linear-gradient(135deg, #22D3EE 0%, #FFFFFF 80%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }

    h2 {
      font-size: 2.5rem;
      font-weight: 700;
      color: var(--text-white);
    }

    h3 {
      font-size: 1.5rem;
      font-weight: 600;
      color: var(--text-white);
    }

    h4 {
      font-size: 1.25rem;
      font-weight: 600;
      color: var(--light-purple);
    }

    .text-gradient {
      background: linear-gradient(135deg, #22D3EE 0%, #A855F7 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }

    .container-main {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }

    /* 导航栏 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 50;
      background: rgba(11, 11, 15, 0.75);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid transparent;
      transition: background 0.3s, border-color 0.3s;
    }

    .navbar.scrolled {
      background: rgba(11, 11, 15, 0.95);
      border-bottom: 1px solid rgba(168, 85, 247, 0.25);
    }

    .nav-link {
      color: var(--text-gray);
      font-size: 0.95rem;
      font-weight: 500;
      transition: color 0.2s;
      position: relative;
    }

    .nav-link:hover,
    .nav-link.active {
      color: var(--text-white);
    }

    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--neon-cyan);
      transition: width 0.3s ease;
    }

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

    .btn-primary {
      background: var(--gradient-main);
      color: white;
      font-weight: 600;
      border-radius: var(--radius-btn);
      padding: 0.6rem 1.5rem;
      transition: all 0.25s;
      box-shadow: 0 4px 14px rgba(34, 211, 238, 0.3);
      display: inline-block;
      text-align: center;
    }

    .btn-primary:hover {
      filter: brightness(1.15);
      transform: translateY(-2px);
      box-shadow: 0 16px 40px rgba(34, 211, 238, 0.45);
    }

    .btn-outline {
      background: transparent;
      border: 1px solid var(--neon-cyan);
      color: var(--neon-cyan);
      font-weight: 600;
      border-radius: var(--radius-btn);
      padding: 0.6rem 1.5rem;
      transition: all 0.25s;
    }

    .btn-outline:hover {
      background: rgba(34, 211, 238, 0.1);
      border-color: var(--primary-purple);
      color: white;
      box-shadow: 0 0 15px rgba(168, 85, 247, 0.4);
    }

    /* 卡片系统 */
    .card-dark {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      transition: transform 0.25s, box-shadow 0.3s;
      padding: 1.8rem;
    }

    .card-dark:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
      border-color: var(--border-glow);
    }

    .icon-box {
      width: 48px;
      height: 48px;
      background: rgba(168, 85, 247, 0.15);
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 1rem;
    }

    /* 手风琴 */
    .faq-item {
      background: var(--card-bg);
      border-radius: 8px;
      margin-bottom: 0.75rem;
      overflow: hidden;
    }

    .faq-question {
      padding: 1.25rem 1.5rem;
      font-weight: 600;
      color: var(--text-white);
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.3s;
      background: #222240;
      color: var(--text-gray);
      padding: 0 1.5rem;
    }

    .faq-item.open .faq-answer {
      max-height: 200px;
      padding: 1rem 1.5rem;
    }

    .faq-item.open .faq-question {
      border-left: 3px solid var(--neon-cyan);
    }

    /* 装饰线条 */
    .decor-line {
      width: 40px;
      height: 3px;
      background: var(--neon-cyan);
      margin-bottom: 0.5rem;
    }

    @media (max-width: 768px) {
      .navbar-menu {
        display: none;
        position: fixed;
        top: 64px;
        left: 0;
        width: 100%;
        height: calc(100vh - 64px);
        background: rgba(11, 11, 15, 0.98);
        flex-direction: column;
        align-items: flex-start;
        padding: 2rem;
        gap: 1.5rem;
      }
      .navbar-menu.open {
        display: flex;
      }
    }