/* roulang page: index */
/* ===== 设计变量与全局重置 ===== */
    :root {
      --primary: #1B1C3E;
      --primary-hover: #2A2B52;
      --accent: #D9A066;
      --accent-hover: #C18A4F;
      --highlight-bg: #F0E5D8;
      --bg-warm: #FAF9F7;
      --text-main: #1E1E1E;
      --text-muted: #555555;
      --text-light: #777777;
      --border-soft: #E5E0DA;
      --success-blue: #4A7C96;
      --card-shadow: 0 4px 24px rgba(27,28,62,0.06);
      --card-shadow-hover: 0 8px 32px rgba(27,28,62,0.12);
      --radius-card: 16px;
      --radius-btn: 8px;
      --transition-smooth: all 0.35s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    }

    * {
      box-sizing: border-box;
    }

    body {
      font-family: 'Noto Sans SC', 'Inter', system-ui, -apple-system, sans-serif;
      background-color: var(--bg-warm);
      color: var(--text-main);
      line-height: 1.75;
      margin: 0;
      padding: 0;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition-smooth);
    }

    button, input {
      font-family: inherit;
    }

    .container {
      max-width: 1200px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }

    @media (max-width: 768px) {
      .container {
        padding-left: 1rem;
        padding-right: 1rem;
      }
    }

    /* 按钮系统 */
    .btn-primary {
      background: var(--primary);
      color: #FFFFFF;
      border: none;
      border-radius: var(--radius-btn);
      padding: 0.85rem 2rem;
      font-weight: 600;
      font-size: 0.95rem;
      letter-spacing: 0.03em;
      transition: var(--transition-smooth);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
      box-shadow: 0 4px 12px rgba(27,28,62,0.15);
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      box-shadow: 0 6px 20px rgba(27,28,62,0.25);
      transform: translateY(-2px);
    }

    .btn-secondary {
      background: transparent;
      color: var(--primary);
      border: 1.5px solid var(--primary);
      border-radius: var(--radius-btn);
      padding: 0.85rem 2rem;
      font-weight: 600;
      font-size: 0.95rem;
      letter-spacing: 0.03em;
      transition: var(--transition-smooth);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
    }
    .btn-secondary:hover {
      background: var(--primary);
      color: #FFFFFF;
    }

    .btn-accent {
      background: var(--accent);
      color: #FFFFFF;
      border: none;
    }
    .btn-accent:hover {
      background: var(--accent-hover);
      box-shadow: 0 6px 20px rgba(217,160,102,0.3);
    }

    /* 卡片系统 */
    .card {
      background: #FFFFFF;
      border-radius: var(--radius-card);
      box-shadow: var(--card-shadow);
      border: 1px solid var(--border-soft);
      transition: var(--transition-smooth);
      overflow: hidden;
    }
    .card:hover {
      box-shadow: var(--card-shadow-hover);
      border-color: var(--accent);
      transform: translateY(-4px);
    }

    .card-image {
      border-radius: 12px 12px 0 0;
      object-fit: cover;
      width: 100%;
      aspect-ratio: 16/10;
      background-color: #E5E0DA; /* 占位色 */
    }

    /* 导航栏 */
    .navbar {
      position: sticky;
      top: 0;
      z-index: 100;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-soft);
      transition: box-shadow 0.3s ease;
    }
    .navbar.scrolled {
      box-shadow: 0 2px 16px rgba(0,0,0,0.06);
    }

    .nav-link {
      font-weight: 500;
      color: var(--text-main);
      padding: 0.5rem 0.75rem;
      border-radius: 6px;
      transition: color 0.2s;
    }
    .nav-link:hover {
      color: var(--accent);
    }

    /* 移动端菜单 */
    .mobile-menu {
      display: none;
      flex-direction: column;
      background: rgba(255,255,255,0.98);
      backdrop-filter: blur(12px);
      position: absolute;
      top: 100%;
      left: 0;
      width: 100%;
      border-bottom: 1px solid var(--border-soft);
      padding: 1rem 1.5rem;
    }
    #menu-toggle:checked ~ .mobile-menu {
      display: flex;
    }

    /* Hero 星空背景 */
    .hero-bg {
      background: var(--primary);
      position: relative;
      overflow: hidden;
    }
    .star-field {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: radial-gradient(1px 1px at 20% 30%, rgba(255,255,255,0.8), transparent),
                  radial-gradient(1px 1px at 60% 20%, rgba(255,255,255,0.7), transparent),
                  radial-gradient(1.5px 1.5px at 80% 50%, rgba(255,255,255,0.9), transparent),
                  radial-gradient(1px 1px at 40% 70%, rgba(240,229,216,0.8), transparent),
                  radial-gradient(1px 1px at 10% 80%, rgba(255,255,255,0.6), transparent);
      animation: starDrift 25s linear infinite;
    }
    @keyframes starDrift {
      0% { transform: translateY(0) translateX(0); }
      50% { transform: translateY(-15px) translateX(10px); }
      100% { transform: translateY(0) translateX(0); }
    }
    .login-card {
      border-radius: 20px;
      background: #FFFFFF;
      box-shadow: 0 20px 60px rgba(0,0,0,0.3);
      animation: slideInRight 0.8s ease-out;
    }
    @keyframes slideInRight {
      from { opacity: 0; transform: translateX(40px); }
      to { opacity: 1; transform: translateX(0); }
    }

    /* 流程连接线 */
    .process-line::after {
      content: '';
      position: absolute;
      top: 50%;
      left: 100%;
      width: 100%;
      height: 2px;
      background: var(--accent);
      transform: translateY(-50%);
      transition: width 0.6s ease;
    }
    .process-step:hover .process-line::after {
      width: 110%;
    }

    /* FAQ 手风琴 */
    .faq-item {
      border-top: 1px solid var(--border-soft);
    }
    .faq-question {
      cursor: pointer;
      padding: 1.25rem 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.4s ease;
      color: var(--text-muted);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 1.25rem;
    }
    .faq-icon {
      transition: transform 0.3s ease;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }

    /* 动效降级 */
    @media (prefers-reduced-motion: reduce) {
      *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
      }
    }

    /* 响应式微调 */
    @media (max-width: 1023px) {
      .process-line::after { display: none; }
      .case-card {
        flex-direction: column;
      }
    }