/* roulang page: index */
:root {
      --primary: #7C3AED;
      --primary-glow: #9F5CF0;
      --secondary: #06D6A0;
      --accent: #F97316;
      --deep-bg: #0F0A1A;
      --darker-bg: #0A0612;
      --light-bg: #F8F7FF;
      --card-bg: #FFFFFF;
      --card-dark-bg: rgba(255,255,255,0.05);
      --text-light: #F0E6FF;
      --text-dark: #1E1B2E;
      --text-muted: #A094B8;
      --border-light: #D8D0E8;
      --border-card: #E8E4F0;
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-tag: 6px;
      --shadow-card: 0 2px 12px rgba(0,0,0,0.05);
      --shadow-hover: 0 8px 30px rgba(124,58,237,0.15);
      --font-sans: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
      --font-display: "Outfit", "Inter", sans-serif;
    }
    * {
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--light-bg);
      color: var(--text-dark);
      line-height: 1.7;
      margin: 0;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
    }
    .container {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }
    /* 导航 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 50;
      background: rgba(15, 10, 26, 0.85);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(216, 208, 232, 0.1);
      transition: background 0.3s;
    }
    .navbar.scrolled {
      background: rgba(10, 6, 18, 0.95);
    }
    .nav-link {
      font-size: 0.875rem;
      font-weight: 500;
      color: var(--text-light);
      margin-left: 2rem;
      position: relative;
      padding: 0.5rem 0;
      transition: color 0.2s;
    }
    .nav-link:hover, .nav-link.active {
      color: var(--secondary);
    }
    .nav-link.active::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 100%;
      height: 2px;
      background: var(--secondary);
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      font-weight: 600;
      padding: 0.75rem 1.75rem;
      border-radius: var(--radius-btn);
      display: inline-block;
      transition: all 0.2s;
      border: none;
      box-shadow: 0 4px 12px rgba(124,58,237,0.3);
    }
    .btn-primary:hover {
      background: #6D28D9;
      box-shadow: 0 0 20px rgba(124,58,237,0.5);
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      border: 1px solid var(--secondary);
      color: var(--secondary);
      font-weight: 600;
      padding: 0.75rem 1.75rem;
      border-radius: var(--radius-btn);
      display: inline-block;
      transition: all 0.2s;
    }
    .btn-outline:hover {
      background: rgba(6,214,160,0.1);
      border-color: #04c48c;
    }
    /* 汉堡菜单 */
    .mobile-menu {
      display: none;
      flex-direction: column;
      position: fixed;
      top: 70px;
      left: 0;
      width: 100%;
      background: var(--deep-bg);
      padding: 2rem 1.5rem;
      gap: 1.5rem;
      border-bottom: 1px solid rgba(255,255,255,0.1);
    }
    .mobile-menu a {
      font-size: 1.2rem;
      font-weight: 600;
      color: var(--text-light);
    }
    /* 区块间距 */
    section {
      padding-top: 5rem;
      padding-bottom: 5rem;
    }
    @media (max-width: 768px) {
      section {
        padding-top: 3.5rem;
        padding-bottom: 3.5rem;
      }
    }
    /* 卡片 */
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      border: 1px solid var(--border-card);
      transition: all 0.25s ease;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
      border-color: rgba(124,58,237,0.3);
    }
    .dark-card {
      background: rgba(255,255,255,0.04);
      backdrop-filter: blur(4px);
      border: 1px solid rgba(255,255,255,0.08);
      border-radius: var(--radius-card);
    }
    /* 对比表 */
    .tier-popular {
      border: 2px solid var(--primary);
      box-shadow: 0 0 25px rgba(124,58,237,0.3);
      position: relative;
    }
    .badge-popular {
      background: var(--accent);
      color: white;
      font-size: 0.75rem;
      font-weight: 700;
      padding: 0.25rem 1rem;
      border-radius: 20px;
      position: absolute;
      top: -12px;
      left: 50%;
      transform: translateX(-50%);
    }
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }
    .faq-question {
      font-weight: 600;
      padding: 1.2rem 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--text-dark);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s;
      padding: 0 0;
      color: #3a3550;
      font-size: 0.95rem;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding: 0 0 1.5rem 0;
      border-left: 3px solid var(--primary);
      padding-left: 1rem;
    }
    .faq-icon {
      color: var(--secondary);
      font-size: 1.5rem;
      font-weight: 400;
    }
    /* 瀑布流 */
    .masonry {
      column-gap: 1.25rem;
    }
    @media (min-width: 768px) {
      .masonry {
        columns: 2;
      }
    }
    @media (min-width: 1024px) {
      .masonry {
        columns: 3;
      }
    }
    .masonry-item {
      break-inside: avoid;
      margin-bottom: 1.25rem;
      border-radius: var(--radius-card);
      overflow: hidden;
      background: #fff;
      box-shadow: 0 4px 10px rgba(0,0,0,0.04);
      transition: transform 0.2s;
    }
    .masonry-item:hover {
      transform: scale(1.02);
    }