/* roulang page: index */
:root {
      --primary: #E43D2A;
      --primary-dark: #C8321F;
      --primary-light: rgba(228, 61, 42, 0.1);
      --accent: #F5A623;
      --accent-light: rgba(245, 166, 35, 0.15);
      --gray-dark: #1E1E1E;
      --gray-mid: #5C5C5C;
      --gray-light: #8E8E8E;
      --gray-bg: #F0F2F5;
      --white: #FFFFFF;
      --warm-white: #FAF9F6;
      --border-light: #E5E7EB;
      --shadow-sm: 0 2px 12px rgba(0,0,0,0.06);
      --shadow-md: 0 6px 20px rgba(0,0,0,0.10);
      --shadow-lg: 0 12px 32px rgba(0,0,0,0.12);
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 16px;
      --transition: 0.25s ease;
      --font-sans: "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;
      --font-zh: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --max-width: 1200px;
      --nav-height: 72px;
      --nav-height-mobile: 60px;
    }

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

    html {
      scroll-behavior: smooth;
      scroll-padding-top: var(--nav-height);
    }

    body {
      font-family: var(--font-zh), var(--font-sans);
      background-color: var(--warm-white);
      color: var(--gray-dark);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

    .container {
      max-width: var(--max-width);
      margin-left: auto;
      margin-right: auto;
      padding-left: 24px;
      padding-right: 24px;
    }

    img {
      display: block;
      max-width: 100%;
      height: auto;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s;
    }

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      transition: all 0.2s ease;
    }

    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      background: var(--white);
      z-index: 1000;
      display: flex;
      align-items: center;
      border-bottom: 1px solid transparent;
      transition: box-shadow 0.25s, border-color 0.25s;
    }

    .site-header.scrolled {
      box-shadow: 0 1px 4px rgba(0,0,0,0.06);
      border-color: var(--border-light);
    }

    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }

    .logo {
      font-weight: 700;
      font-size: 24px;
      color: var(--primary);
      display: flex;
      align-items: baseline;
      gap: 6px;
      letter-spacing: -0.3px;
    }

    .logo .domain {
      font-size: 12px;
      font-weight: 500;
      color: var(--gray-light);
      margin-left: 4px;
    }

    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
    }

    .nav-menu a {
      font-size: 16px;
      font-weight: 500;
      color: var(--gray-dark);
      transition: color 0.2s;
      white-space: nowrap;
    }

    .nav-menu a:hover {
      color: var(--primary);
    }

    .btn-primary {
      background: var(--primary);
      color: var(--white);
      border: none;
      padding: 14px 32px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 16px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: background 0.2s, transform 0.1s;
    }

    .btn-primary:hover {
      background: var(--primary-dark);
    }

    .btn-outline {
      background: transparent;
      color: var(--primary);
      border: 2px solid var(--primary);
      padding: 12px 30px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 16px;
    }

    .btn-outline:hover {
      background: var(--primary-light);
    }

    .btn-white {
      background: var(--white);
      color: var(--primary);
      border: none;
      padding: 14px 32px;
      border-radius: var(--radius-sm);
      font-weight: 600;
    }

    .btn-white-outline {
      background: transparent;
      color: var(--white);
      border: 2px solid var(--white);
      padding: 12px 30px;
      border-radius: var(--radius-sm);
      font-weight: 600;
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 6px;
      background: transparent;
      border: none;
      padding: 4px;
    }

    .hamburger span {
      width: 28px;
      height: 3px;
      background: var(--primary);
      border-radius: 4px;
      transition: 0.2s;
    }

    /* 卡片系统 */
    .card {
      background: var(--white);
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-sm);
      transition: transform 0.25s ease, box-shadow 0.25s ease;
    }

    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }

    /* 板块间距 */
    section {
      padding: 100px 0;
    }

    .section-title {
      font-size: 28px;
      font-weight: 600;
      line-height: 1.36;
      margin-bottom: 16px;
      color: var(--gray-dark);
    }

    .section-sub {
      font-size: 18px;
      color: var(--gray-mid);
      max-width: 640px;
      margin-bottom: 48px;
    }

    /* FAQ 手风琴 */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }

    .faq-question {
      width: 100%;
      background: transparent;
      border: none;
      padding: 20px 0;
      font-size: 18px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      text-align: left;
      color: var(--gray-dark);
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s ease;
      background: #F9FAFB;
      border-radius: var(--radius-sm);
      color: var(--gray-mid);
    }

    .faq-answer.open {
      max-height: 200px;
      padding: 16px;
    }

    .faq-icon {
      font-size: 24px;
      color: var(--primary);
      transition: transform 0.2s;
    }

    /* 响应式 */
    @media (max-width: 1023px) {
      .container {
        padding-left: 20px;
        padding-right: 20px;
      }
      section {
        padding: 80px 0;
      }
    }

    @media (max-width: 767px) {
      :root {
        --nav-height: var(--nav-height-mobile);
      }
      html {
        scroll-padding-top: var(--nav-height-mobile);
      }
      .site-header {
        height: var(--nav-height-mobile);
      }
      .nav-menu {
        display: none;
        position: fixed;
        top: var(--nav-height-mobile);
        left: 0;
        width: 100%;
        background: var(--warm-white);
        flex-direction: column;
        padding: 32px 24px;
        gap: 24px;
        box-shadow: 0 10px 20px rgba(0,0,0,0.05);
      }
      .nav-menu.active {
        display: flex;
      }
      .hamburger {
        display: flex;
      }
      .desktop-cta {
        display: none;
      }
      section {
        padding: 60px 0;
      }
      .section-title {
        font-size: 24px;
      }
      h1 {
        font-size: 28px !important;
        line-height: 1.3 !important;
      }
    }

    @media (min-width: 768px) {
      .mobile-cta {
        display: none;
      }
    }

    /* 价格高亮 */
    .pricing-highlight {
      border: 2px solid var(--primary);
      position: relative;
    }

    .badge-accent {
      background: var(--accent);
      color: var(--white);
      padding: 4px 12px;
      border-radius: 4px;
      font-size: 13px;
      font-weight: 600;
      position: absolute;
      top: -12px;
      left: 50%;
      transform: translateX(-50%);
    }

    .text-accent {
      color: var(--accent);
    }

    .bg-primary-soft {
      background: var(--primary-light);
    }