/* roulang page: index */
:root {
      --primary: #4E6EF2;
      --primary-light: rgba(78, 110, 242, 0.1);
      --primary-soft: rgba(78, 110, 242, 0.06);
      --secondary-green: #00B578;
      --secondary-orange: #FF9F0A;
      --error: #FA5151;
      --bg: #F5F6FA;
      --surface: #FFFFFF;
      --text-primary: #1F2329;
      --text-secondary: #86909C;
      --border: #E5E8EF;
      --shadow-sm: 0 2px 8px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 8px;
      --transition: 200ms ease;
    }

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

    body {
      font-family: 'PingFang SC', 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
      background-color: var(--bg);
      color: var(--text-primary);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

    a {
      color: var(--primary);
      text-decoration: none;
      transition: color var(--transition), text-decoration var(--transition);
    }
    a:hover {
      text-decoration: underline;
    }

    button, input, textarea {
      font-family: inherit;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding-left: 24px;
      padding-right: 24px;
    }

    /* header / navigation */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: var(--surface);
      border-bottom: 1px solid var(--border);
      height: 64px;
      display: flex;
      align-items: center;
      transition: box-shadow 0.3s ease;
    }
    .site-header.scrolled {
      box-shadow: var(--shadow-sm);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      font-size: 22px;
      font-weight: 700;
      color: var(--text-primary);
      letter-spacing: -0.5px;
    }
    .logo span {
      color: var(--primary);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      font-size: 15px;
      font-weight: 500;
      color: var(--text-secondary);
      transition: color 0.2s;
      position: relative;
    }
    .nav-links a:hover {
      color: var(--primary);
      text-decoration: none;
    }
    .nav-links a.active {
      color: var(--primary);
    }
    .nav-links a.active::after {
      content: '';
      position: absolute;
      bottom: -6px;
      left: 0;
      width: 100%;
      height: 2px;
      background: var(--primary);
      border-radius: 2px;
    }

    /* mobile bottom nav */
    .mobile-bottom-nav {
      display: none;
    }

    /* buttons */
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      border: none;
      cursor: pointer;
      transition: filter 0.2s, transform 0.2s, box-shadow 0.2s;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      box-shadow: 0 2px 6px rgba(78,110,242,0.2);
    }
    .btn-primary:hover {
      filter: brightness(1.1);
      transform: translateY(-2px);
      box-shadow: 0 6px 18px rgba(78,110,242,0.3);
    }

    .btn-secondary {
      background: transparent;
      color: var(--primary);
      border: 1px solid var(--primary);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      cursor: pointer;
      transition: background 0.2s, transform 0.2s;
    }
    .btn-secondary:hover {
      background: var(--primary-light);
      transform: translateY(-1px);
    }

    .btn-white {
      background: white;
      color: var(--primary);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      border: none;
      cursor: pointer;
      transition: 0.2s;
    }
    .btn-white:hover {
      background: #f0f2ff;
    }

    /* cards */
    .card {
      background: var(--surface);
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      transition: transform 0.3s, box-shadow 0.3s;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }

    /* sections spacing */
    .section {
      padding: 80px 0;
    }

    /* typography */
    h1 {
      font-size: 36px;
      font-weight: 700;
      line-height: 1.3;
    }
    h2 {
      font-size: 28px;
      font-weight: 600;
      line-height: 1.4;
    }
    h3 {
      font-size: 22px;
      font-weight: 500;
      line-height: 1.5;
    }
    h4 {
      font-size: 18px;
      font-weight: 500;
    }

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

    /* Hero */
    .hero-bg {
      background: linear-gradient(135deg, #f8faff 0%, #f0f3ff 100%);
    }

    /* Results bar */
    .results-strip {
      background: var(--primary);
      color: white;
      border-radius: 16px;
      padding: 40px 0;
    }

    /* testimonial card */
    .testimonial-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      border-left: 4px solid var(--primary);
      position: relative;
    }
    .testimonial-card::before {
      content: "“";
      font-size: 48px;
      color: var(--primary);
      opacity: 0.3;
      position: absolute;
      top: 8px;
      left: 16px;
      line-height: 1;
    }

    /* FAQ */
    .faq-item {
      background: var(--surface);
      border-radius: var(--radius-card);
      margin-bottom: 16px;
      box-shadow: var(--shadow-sm);
    }
    .faq-question {
      padding: 20px 24px;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      padding: 0 24px;
      color: var(--text-secondary);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 20px;
    }
    .faq-icon {
      transition: transform 0.3s;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }

    /* footer */
    .site-footer {
      background: var(--surface);
      border-top: 1px solid var(--border);
      padding: 40px 0 20px;
      font-size: 14px;
      color: var(--text-secondary);
    }

    /* animations */
    .fade-up {
      opacity: 0;
      transform: translateY(20px);
      transition: opacity 0.4s ease, transform 0.4s ease;
    }
    .fade-up.visible {
      opacity: 1;
      transform: translateY(0);
    }

    /* input */
    .input-field {
      background: white;
      border: 1px solid var(--border);
      border-radius: var(--radius-input);
      padding: 12px 16px;
      width: 100%;
      transition: border 0.2s, box-shadow 0.2s;
      outline: none;
    }
    .input-field:focus {
      border-color: var(--primary);
      box-shadow: 0 0 0 3px rgba(78,110,242,0.2);
    }

    /* responsive */
    @media (max-width: 1024px) {
      .container {
        padding-left: 24px;
        padding-right: 24px;
      }
      h1 { font-size: 32px; }
      h2 { font-size: 26px; }
    }
    @media (max-width: 768px) {
      .site-header .nav-links {
        display: none;
      }
      .mobile-bottom-nav {
        display: flex;
        position: fixed;
        bottom: 0;
        left: 0;
        width: 100%;
        height: 56px;
        background: white;
        box-shadow: 0 -4px 12px rgba(0,0,0,0.05);
        justify-content: space-around;
        align-items: center;
        z-index: 55;
        padding: 0 16px;
      }
      .mobile-nav-item {
        display: flex;
        flex-direction: column;
        align-items: center;
        color: var(--text-secondary);
        font-size: 12px;
        gap: 2px;
        text-decoration: none;
      }
      .mobile-nav-item.active {
        color: var(--primary);
        font-weight: 600;
      }
      .mobile-cta {
        background: var(--primary);
        color: white;
        padding: 8px 20px;
        border-radius: 20px;
        font-weight: 600;
      }
      .section {
        padding: 60px 0;
      }
      h1 { font-size: 28px; }
      h2 { font-size: 22px; }
      .hero-text {
        text-align: center;
      }
    }
    @media (max-width: 640px) {
      .container {
        padding-left: 16px;
        padding-right: 16px;
      }
      h1 { font-size: 26px; }
    }