:root {
      --primary: #ff2d78;
      --primary-hover: #e01e65;
      --bg: #ffffff;
      --bg-light: #fff5f8;
      --text: #222222;
      --text-muted: #666666;
      --border: #f0f0f0;
      --radius: 12px;
      --nav-height: 64px;
    }

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

    html {
      scroll-behavior: smooth;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    }

    body {
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }

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

    a {
      text-decoration: none;
      color: inherit;
    }

    .container {
      width: 100%;
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
    }

    /* Nav */
    header {
      position: sticky;
      top: 0;
      background-color: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--border);
      z-index: 1000;
    }

    .nav-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: var(--nav-height);
    }

    .logo-group {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: bold;
      font-size: 18px;
    }

    .logo-group img {
      height: 32px;
      border-radius: 6px;
    }

    .nav-links {
      display: flex;
      gap: 24px;
      align-items: center;
    }

    .nav-links a {
      font-size: 15px;
      color: var(--text-muted);
      transition: color 0.3s;
    }

    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
      font-weight: 500;
    }

    .btn-download-nav {
      background-color: var(--primary);
      color: #fff !important;
      padding: 8px 20px;
      border-radius: 20px;
      font-weight: 500;
      transition: background 0.3s;
    }

    .btn-download-nav:hover {
      background-color: var(--primary-hover);
    }

    .menu-btn {
      display: none;
      background: none;
      border: none;
      font-size: 16px;
      cursor: pointer;
      color: var(--text);
    }

    /* Sections Common */
    section {
      padding: 80px 0;
      scroll-margin-top: calc(var(--nav-height) + 20px);
    }

    .section-title {
      font-size: 32px;
      font-weight: bold;
      margin-bottom: 12px;
      text-align: center;
    }

    .section-desc {
      text-align: center;
      color: var(--text-muted);
      margin-bottom: 48px;
      font-size: 16px;
    }

    /* Hero */
    #hero {
      background-color: var(--bg-light);
      text-align: center;
      padding: 100px 0;
    }

    #hero h1 {
      font-size: 48px;
      line-height: 1.2;
      margin-bottom: 20px;
      color: var(--primary);
    }

    #hero p {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 40px;
      max-width: 600px;
      margin-left: auto;
      margin-right: auto;
    }

    .btn-download-hero {
      display: inline-block;
      background-color: var(--primary);
      color: #fff;
      font-size: 20px;
      font-weight: bold;
      padding: 16px 48px;
      border-radius: 30px;
      box-shadow: 0 8px 24px rgba(255, 45, 120, 0.3);
      transition: transform 0.3s, box-shadow 0.3s;
    }

    .btn-download-hero:hover {
      transform: translateY(-2px);
      box-shadow: 0 12px 32px rgba(255, 45, 120, 0.4);
    }

    .hero-img {
      max-width: 800px;
      margin: 60px auto 0;
      border-radius: var(--radius);
      box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    }

    /* Grid Layouts */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }

    .card {
      background: #fff;
      border-radius: var(--radius);
      overflow: hidden;
      border: 1px solid var(--border);
      transition: transform 0.3s;
    }

    .card:hover {
      transform: translateY(-4px);
      box-shadow: 0 12px 24px rgba(0, 0, 0, 0.05);
    }

    .card img {
      width: 100%;
      aspect-ratio: 3/4;
      object-fit: cover;
    }

    .card-wide img {
      aspect-ratio: 16/9;
    }

    .card-content {
      padding: 20px;
    }

    .card-content h3 {
      font-size: 18px;
      margin-bottom: 8px;
    }

    .card-content p {
      font-size: 14px;
      color: var(--text-muted);
    }

    /* FAQ */
    .faq-group {
      margin-bottom: 32px;
    }

    .faq-group h3 {
      font-size: 20px;
      color: var(--primary);
      margin-bottom: 16px;
      padding-bottom: 8px;
      border-bottom: 1px solid var(--border);
    }

    .faq-item {
      margin-bottom: 16px;
    }

    .faq-item strong {
      display: block;
      margin-bottom: 4px;
      font-size: 16px;
    }

    .faq-item p {
      font-size: 14px;
      color: var(--text-muted);
    }

    /* Steps */
    .step-card {
      background: #fff;
      border-radius: var(--radius);
      border: 1px solid var(--border);
      overflow: hidden;
      margin-bottom: 24px;
    }

    .step-card img {
      width: 100%;
      aspect-ratio: 16/9;
      object-fit: cover;
    }

    /* Footer */
    footer {
      background-color: #fafafa;
      padding: 40px 0;
      text-align: center;
      color: #999;
      font-size: 12px;
      border-top: 1px solid var(--border);
    }

    footer p {
      margin-bottom: 8px;
    }

    footer a {
      color: #999;
      transition: color 0.3s;
    }

    footer a:hover {
      color: var(--text-muted);
    }

    /* Responsive */
    @media (max-width: 900px) {
      .nav-links {
        display: none;
        position: absolute;
        top: var(--nav-height);
        left: 0;
        width: 100%;
        background: #fff;
        flex-direction: column;
        padding: 20px;
        border-bottom: 1px solid var(--border);
        box-shadow: 0 10px 15px rgba(0,0,0,0.05);
      }
      .nav-links.active {
        display: flex;
      }
      .menu-btn {
        display: block;
      }
      #hero h1 {
        font-size: 36px;
      }
      .grid-3 {
        grid-template-columns: repeat(2, 1fr);
      }
    }

    @media (max-width: 768px) {
      section {
        padding: 60px 0;
      }
      .section-title {
        font-size: 26px;
      }
      .grid-3, .grid-2 {
        grid-template-columns: 1fr;
      }
      #hero {
        padding: 60px 0;
      }
      #hero h1 {
        font-size: 28px;
      }
      #hero p {
        font-size: 16px;
      }
    }