:root {
      --bg-base: #f4f7fc;
      --bg-gradient: linear-gradient(160deg, #eef3ff 0%, #faf5ff 40%, #f0f8ff 100%);
      --card-bg: rgba(255, 255, 255, 0.85);
      --card-solid: #ffffff;
      --primary: #4a3aff;
      --primary-dark: #3427c9;
      --accent: #b44aff;
      --accent-soft: #f0e6ff;
      --text-dark: #1a1a2e;
      --text-body: #2e2e4a;
      --text-muted: #5a5a7a;
      --border-light: rgba(74, 58, 255, 0.12);
      --shadow-sm: 0 2px 8px rgba(74, 58, 255, 0.06);
      --shadow-md: 0 8px 30px rgba(74, 58, 255, 0.10);
      --shadow-lg: 0 20px 50px rgba(74, 58, 255, 0.14);
      --radius-sm: 10px;
      --radius-md: 18px;
      --radius-lg: 28px;
      --font-sans: 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'Helvetica Neue', Arial, sans-serif;
      --container-max: 1200px;
      --container-pad: 20px;
      --transition: 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
    }
    body {
      font-family: var(--font-sans);
      color: var(--text-body);
      background: var(--bg-gradient);
      background-attachment: fixed;
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding-left: var(--container-pad);
      padding-right: var(--container-pad);
      width: 100%;
    }
    h1, h2, h3, h4 {
      color: var(--text-dark);
      font-weight: 700;
      line-height: 1.3;
    }
    h1 { font-size: clamp(1.9rem, 5vw, 3.2rem); letter-spacing: -0.02em; }
    h2 { font-size: clamp(1.5rem, 3.5vw, 2.2rem); margin-bottom: 1rem; }
    h3 { font-size: clamp(1.1rem, 2vw, 1.35rem); }
    p { margin-bottom: 0.8rem; }
    a { text-decoration: none; color: var(--primary); transition: color var(--transition); }
    a:hover { color: var(--accent); }
    img { max-width: 100%; height: auto; display: block; }
    ul { list-style: none; }

    /* Header */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: rgba(255, 255, 255, 0.78);
      backdrop-filter: blur(18px);
      -webkit-backdrop-filter: blur(18px);
      border-bottom: 1px solid rgba(74, 58, 255, 0.08);
      transition: box-shadow var(--transition);
    }
    .site-header.scrolled {
      box-shadow: var(--shadow-sm);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 12px;
      padding-top: 14px;
      padding-bottom: 14px;
      flex-wrap: wrap;
    }
    .brand {
      display: flex;
      align-items: center;
      gap: 10px;
      flex-shrink: 0;
    }
    .brand .ai-page-logo {
      max-height: 40px;
      width: auto;
    }
    .brand-text {
      font-size: 1.2rem;
      font-weight: 800;
      color: var(--text-dark);
      letter-spacing: 0.5px;
      white-space: nowrap;
    }
    .nav-toggle {
      display: none;
      background: none;
      border: 1px solid var(--border-light);
      border-radius: 8px;
      padding: 8px 12px;
      cursor: pointer;
      color: var(--text-dark);
      font-size: 1.2rem;
      line-height: 1;
      transition: background var(--transition);
    }
    .nav-toggle:hover { background: var(--accent-soft); }
    .nav-links {
      display: flex;
      align-items: center;
      flex-wrap: wrap;
      gap: 0;
      margin-left: auto;
    }
    .nav-links li { display: inline-block; }
    .nav-links a {
      display: inline-block;
      padding: 8px 14px;
      font-size: 0.92rem;
      font-weight: 500;
      color: var(--text-body);
      border-radius: 8px;
      transition: background var(--transition), color var(--transition);
      white-space: nowrap;
    }
    .nav-links a:hover {
      background: var(--accent-soft);
      color: var(--primary);
    }
    .nav-cta {
      display: inline-block;
      padding: 8px 18px;
      background: var(--primary);
      color: #fff !important;
      border-radius: 50px;
      font-weight: 600;
      font-size: 0.9rem;
      transition: transform var(--transition), box-shadow var(--transition), background var(--transition);
    }
    .nav-cta:hover {
      background: var(--primary-dark) !important;
      transform: translateY(-1px);
      box-shadow: 0 6px 18px rgba(74, 58, 255, 0.35);
    }

    /* Hero */
    .hero {
      position: relative;
      padding: 80px 0 70px;
      overflow: hidden;
    }
    .hero::before {
      content: '';
      position: absolute;
      top: -30%;
      left: -10%;
      width: 60%;
      height: 80%;
      background: radial-gradient(ellipse, rgba(74, 58, 255, 0.10) 0%, transparent 70%);
      pointer-events: none;
      z-index: 0;
    }
    .hero::after {
      content: '';
      position: absolute;
      bottom: -20%;
      right: -10%;
      width: 50%;
      height: 70%;
      background: radial-gradient(ellipse, rgba(180, 74, 255, 0.08) 0%, transparent 70%);
      pointer-events: none;
      z-index: 0;
    }
    .hero-inner {
      position: relative;
      z-index: 1;
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      gap: 28px;
    }
    .hero-badge {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      padding: 6px 18px;
      background: rgba(74, 58, 255, 0.08);
      border: 1px solid rgba(74, 58, 255, 0.15);
      border-radius: 50px;
      font-size: 0.85rem;
      font-weight: 600;
      color: var(--primary);
      letter-spacing: 0.5px;
    }
    .hero-badge::before {
      content: '';
      width: 7px;
      height: 7px;
      border-radius: 50%;
      background: var(--accent);
      animation: pulse-dot 2s infinite;
    }
    @keyframes pulse-dot {
      0%, 100% { opacity: 1; transform: scale(1); }
      50% { opacity: 0.5; transform: scale(0.8); }
    }
    .hero h1 {
      max-width: 900px;
      background: linear-gradient(135deg, #1a1a2e 30%, #4a3aff 70%, #b44aff 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .hero-sub {
      max-width: 720px;
      font-size: clamp(1rem, 1.6vw, 1.15rem);
      color: var(--text-muted);
      line-height: 1.8;
    }
    .hero-actions {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
      justify-content: center;
    }
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      padding: 14px 34px;
      border-radius: 50px;
      font-weight: 700;
      font-size: 1rem;
      border: none;
      cursor: pointer;
      transition: transform var(--transition), box-shadow var(--transition), background var(--transition);
      text-decoration: none;
      line-height: 1.2;
    }
    .btn-primary {
      background: linear-gradient(135deg, var(--primary), var(--accent));
      color: #fff;
      box-shadow: 0 8px 26px rgba(74, 58, 255, 0.30);
    }
    .btn-primary:hover {
      transform: translateY(-2px);
      box-shadow: 0 12px 34px rgba(74, 58, 255, 0.42);
      color: #fff;
    }
    .btn-outline {
      background: #fff;
      color: var(--primary);
      border: 1.5px solid rgba(74, 58, 255, 0.25);
    }
    .btn-outline:hover {
      background: var(--accent-soft);
      transform: translateY(-2px);
      border-color: var(--primary);
    }
    .hero-metrics {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 16px;
      width: 100%;
      max-width: 860px;
      margin-top: 10px;
    }
    .metric-card {
      background: var(--card-bg);
      backdrop-filter: blur(8px);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 22px 12px;
      text-align: center;
      box-shadow: var(--shadow-sm);
      transition: transform var(--transition), box-shadow var(--transition);
    }
    .metric-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .metric-value {
      font-size: clamp(1.5rem, 2.5vw, 2.2rem);
      font-weight: 800;
      color: var(--primary);
      line-height: 1.2;
    }
    .metric-label {
      font-size: 0.82rem;
      color: var(--text-muted);
      margin-top: 4px;
      font-weight: 500;
    }

    /* Sections */
    .section {
      padding: 68px 0;
      position: relative;
    }
    .section-alt {
      background: rgba(255, 255, 255, 0.45);
      backdrop-filter: blur(4px);
      border-top: 1px solid rgba(74, 58, 255, 0.05);
      border-bottom: 1px solid rgba(74, 58, 255, 0.05);
    }
    .section-header {
      text-align: center;
      max-width: 760px;
      margin: 0 auto 44px;
    }
    .section-header .eyebrow {
      display: inline-block;
      font-size: 0.85rem;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: 2px;
      text-transform: uppercase;
      margin-bottom: 10px;
      padding: 4px 14px;
      background: rgba(74, 58, 255, 0.07);
      border-radius: 30px;
    }
    .section-header h2 {
      margin-bottom: 12px;
    }
    .section-header p {
      color: var(--text-muted);
      font-size: 1rem;
      margin-bottom: 0;
    }

    /* Cards */
    .card-grid {
      display: grid;
      gap: 22px;
    }
    .grid-2 { grid-template-columns: repeat(2, 1fr); }
    .grid-3 { grid-template-columns: repeat(3, 1fr); }
    .grid-4 { grid-template-columns: repeat(4, 1fr); }
    .card {
      background: var(--card-solid);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 28px 24px;
      box-shadow: var(--shadow-sm);
      transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
      display: flex;
      flex-direction: column;
      gap: 10px;
    }
    .card:hover {
      transform: translateY(-5px);
      box-shadow: var(--shadow-md);
      border-color: rgba(74, 58, 255, 0.20);
    }
    .card-icon {
      width: 52px;
      height: 52px;
      border-radius: 14px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 1.5rem;
      background: linear-gradient(135deg, rgba(74, 58, 255, 0.10), rgba(180, 74, 255, 0.10));
      color: var(--primary);
      margin-bottom: 6px;
      flex-shrink: 0;
    }
    .card h3 { margin-bottom: 4px; }
    .card p { color: var(--text-muted); font-size: 0.92rem; margin-bottom: 0; }

    /* Steps */
    .steps {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
      counter-reset: step;
    }
    .step-item {
      position: relative;
      background: var(--card-solid);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 32px 22px 26px;
      box-shadow: var(--shadow-sm);
      transition: transform var(--transition), box-shadow var(--transition);
      counter-increment: step;
    }
    .step-item::before {
      content: counter(step, decimal-leading-zero);
      position: absolute;
      top: 18px;
      right: 20px;
      font-size: 2.4rem;
      font-weight: 900;
      color: rgba(74, 58, 255, 0.08);
      line-height: 1;
    }
    .step-item:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .step-item h3 { font-size: 1.05rem; margin-bottom: 6px; }
    .step-item p { font-size: 0.88rem; color: var(--text-muted); margin-bottom: 0; }

    /* Comparison Table */
    .table-wrap {
      overflow-x: auto;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-light);
      background: var(--card-solid);
      box-shadow: var(--shadow-sm);
    }
    .compare-table {
      width: 100%;
      border-collapse: collapse;
      font-size: 0.92rem;
      min-width: 720px;
    }
    .compare-table th,
    .compare-table td {
      padding: 16px 20px;
      text-align: left;
      border-bottom: 1px solid rgba(74, 58, 255, 0.06);
      vertical-align: top;
    }
    .compare-table thead th {
      background: linear-gradient(135deg, rgba(74, 58, 255, 0.06), rgba(180, 74, 255, 0.06));
      font-weight: 700;
      color: var(--text-dark);
      font-size: 0.95rem;
    }
    .compare-table tbody tr:last-child td { border-bottom: none; }
    .compare-table tbody tr:hover { background: rgba(74, 58, 255, 0.03); }
    .compare-highlight {
      color: var(--primary);
      font-weight: 700;
    }
    .stars {
      color: #f5a623;
      font-size: 1.1rem;
      letter-spacing: 2px;
    }
    .score-badge {
      display: inline-block;
      background: linear-gradient(135deg, var(--primary), var(--accent));
      color: #fff;
      padding: 4px 16px;
      border-radius: 30px;
      font-weight: 700;
      font-size: 0.95rem;
    }

    /* Testimonials */
    .testimonial-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 22px;
    }
    .testimonial-card {
      background: var(--card-solid);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 26px 24px;
      box-shadow: var(--shadow-sm);
      transition: transform var(--transition), box-shadow var(--transition);
      display: flex;
      flex-direction: column;
      gap: 14px;
    }
    .testimonial-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .testimonial-text {
      font-size: 0.92rem;
      color: var(--text-body);
      line-height: 1.7;
      flex: 1;
    }
    .testimonial-author {
      display: flex;
      align-items: center;
      gap: 12px;
      border-top: 1px solid rgba(74, 58, 255, 0.06);
      padding-top: 12px;
    }
    .author-avatar {
      width: 42px;
      height: 42px;
      border-radius: 50%;
      background: linear-gradient(135deg, var(--primary), var(--accent));
      display: flex;
      align-items: center;
      justify-content: center;
      color: #fff;
      font-weight: 700;
      font-size: 1rem;
      flex-shrink: 0;
    }
    .author-info {
      display: flex;
      flex-direction: column;
      line-height: 1.4;
    }
    .author-name {
      font-weight: 700;
      font-size: 0.9rem;
      color: var(--text-dark);
    }
    .author-role {
      font-size: 0.78rem;
      color: var(--text-muted);
    }

    /* FAQ */
    .faq-list {
      display: flex;
      flex-direction: column;
      gap: 12px;
      max-width: 880px;
      margin: 0 auto;
    }
    .faq-item {
      background: var(--card-solid);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-sm);
      overflow: hidden;
      transition: box-shadow var(--transition), border-color var(--transition);
    }
    .faq-item:hover { border-color: rgba(74, 58, 255, 0.18); }
    .faq-item.active {
      box-shadow: var(--shadow-sm);
      border-color: rgba(74, 58, 255, 0.22);
    }
    .faq-question {
      width: 100%;
      text-align: left;
      background: none;
      border: none;
      padding: 18px 22px;
      font-size: 0.98rem;
      font-weight: 600;
      color: var(--text-dark);
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      gap: 14px;
      font-family: inherit;
      transition: background var(--transition);
      line-height: 1.5;
    }
    .faq-question:hover { background: rgba(74, 58, 255, 0.03); }
    .faq-question::after {
      content: '+';
      font-size: 1.4rem;
      font-weight: 400;
      color: var(--primary);
      transition: transform var(--transition);
      flex-shrink: 0;
      line-height: 1;
    }
    .faq-item.active .faq-question::after {
      content: '−';
      transform: rotate(180deg);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.35s ease;
      padding: 0 22px;
      color: var(--text-muted);
      font-size: 0.9rem;
      line-height: 1.7;
    }
    .faq-item.active .faq-answer {
      max-height: 400px;
      padding: 0 22px 20px;
    }

    /* Tags */
    .tag-cloud {
      display: flex;
      flex-wrap: wrap;
      gap: 10px;
      justify-content: center;
    }
    .tag-item {
      display: inline-block;
      padding: 7px 16px;
      background: var(--card-solid);
      border: 1px solid var(--border-light);
      border-radius: 50px;
      font-size: 0.85rem;
      font-weight: 500;
      color: var(--text-body);
      transition: background var(--transition), color var(--transition), transform var(--transition), border-color var(--transition);
      cursor: default;
    }
    .tag-item:hover {
      background: var(--primary);
      color: #fff;
      border-color: var(--primary);
      transform: translateY(-2px);
    }

    /* Form */
    .form-wrapper {
      background: var(--card-solid);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-lg);
      padding: 40px 36px;
      box-shadow: var(--shadow-md);
      max-width: 780px;
      margin: 0 auto;
    }
    .form-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 18px;
    }
    .form-group {
      display: flex;
      flex-direction: column;
      gap: 6px;
    }
    .form-group.full { grid-column: 1 / -1; }
    .form-group label {
      font-size: 0.88rem;
      font-weight: 600;
      color: var(--text-dark);
    }
    .form-group input,
    .form-group select,
    .form-group textarea {
      padding: 13px 16px;
      border: 1.5px solid rgba(74, 58, 255, 0.15);
      border-radius: var(--radius-sm);
      font-size: 0.92rem;
      font-family: inherit;
      color: var(--text-dark);
      background: #fafbff;
      transition: border-color var(--transition), box-shadow var(--transition);
      outline: none;
      width: 100%;
    }
    .form-group input:focus,
    .form-group select:focus,
    .form-group textarea:focus {
      border-color: var(--primary);
      box-shadow: 0 0 0 3px rgba(74, 58, 255, 0.10);
      background: #fff;
    }
    .form-group textarea {
      resize: vertical;
      min-height: 110px;
    }
    .form-submit {
      margin-top: 10px;
      width: 100%;
      padding: 15px;
      border: none;
      border-radius: 50px;
      background: linear-gradient(135deg, var(--primary), var(--accent));
      color: #fff;
      font-size: 1rem;
      font-weight: 700;
      cursor: pointer;
      transition: transform var(--transition), box-shadow var(--transition);
      font-family: inherit;
      letter-spacing: 1px;
    }
    .form-submit:hover {
      transform: translateY(-2px);
      box-shadow: 0 10px 28px rgba(74, 58, 255, 0.35);
    }

    /* Gallery */
    .gallery-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 22px;
    }
    .gallery-item {
      border-radius: var(--radius-md);
      overflow: hidden;
      border: 1px solid var(--border-light);
      box-shadow: var(--shadow-sm);
      transition: transform var(--transition), box-shadow var(--transition);
      background: var(--card-solid);
      display: flex;
      flex-direction: column;
    }
    .gallery-item:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .gallery-item img {
      width: 100%;
      aspect-ratio: 16 / 9;
      object-fit: cover;
      transition: transform 0.5s ease;
    }
    .gallery-item:hover img { transform: scale(1.03); }
    .gallery-caption {
      padding: 16px 20px;
      font-size: 0.9rem;
      font-weight: 600;
      color: var(--text-dark);
      background: var(--card-solid);
    }

    /* Articles */
    .article-list {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 18px;
    }
    .article-item {
      background: var(--card-solid);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 22px 24px;
      box-shadow: var(--shadow-sm);
      transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
      display: flex;
      flex-direction: column;
      gap: 8px;
    }
    .article-item:hover {
      transform: translateY(-3px);
      box-shadow: var(--shadow-md);
      border-color: rgba(74, 58, 255, 0.20);
    }
    .article-item h3 { font-size: 1rem; }
    .article-item p { font-size: 0.86rem; color: var(--text-muted); margin-bottom: 0; }
    .article-tag {
      display: inline-block;
      font-size: 0.72rem;
      font-weight: 600;
      padding: 2px 10px;
      border-radius: 30px;
      background: var(--accent-soft);
      color: var(--primary);
      margin-bottom: 4px;
      width: fit-content;
    }

    /* Footer */
    .site-footer {
      background: #12122a;
      color: #b0b0c8;
      padding: 56px 0 0;
      margin-top: 0;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.4fr;
      gap: 36px;
      padding-bottom: 40px;
      border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    }
    .footer-brand-col .brand-text {
      font-size: 1.15rem;
      color: #ffffff;
      margin-bottom: 14px;
      display: block;
    }
    .footer-brand-col p {
      font-size: 0.86rem;
      line-height: 1.8;
      color: #9d9db8;
      margin-bottom: 14px;
    }
    .footer-col h4 {
      color: #ffffff;
      font-size: 0.95rem;
      margin-bottom: 16px;
      font-weight: 700;
    }
    .footer-col ul {
      display: flex;
      flex-direction: column;
      gap: 10px;
    }
    .footer-col ul a {
      color: #9d9db8;
      font-size: 0.86rem;
      transition: color var(--transition);
    }
    .footer-col ul a:hover { color: #c4b5ff; }
    .footer-contact-item {
      font-size: 0.86rem;
      color: #9d9db8;
      line-height: 1.8;
    }
    .footer-contact-item strong {
      color: #d0d0e8;
      font-weight: 600;
    }
    .kefu-img {
      margin-top: 10px;
      border-radius: 10px;
      width: 110px;
      border: 2px solid rgba(255, 255, 255, 0.1);
    }
    .footer-bottom {
      padding: 22px 0;
      text-align: center;
      font-size: 0.82rem;
      color: #7a7a9a;
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      align-items: center;
      gap: 8px 20px;
    }
    .footer-bottom a { color: #9d9db8; }
    .footer-bottom a:hover { color: #c4b5ff; }
    .friend-links {
      display: flex;
      flex-wrap: wrap;
      gap: 6px 16px;
      justify-content: center;
      padding: 0 0 16px;
      font-size: 0.8rem;
    }
    .friend-links a {
      color: #8a8aa8;
      font-size: 0.8rem;
      transition: color var(--transition);
    }
    .friend-links a:hover { color: #c4b5ff; }

    /* Floating */
    .float-actions {
      position: fixed;
      right: 20px;
      bottom: 30px;
      z-index: 999;
      display: flex;
      flex-direction: column;
      gap: 12px;
      align-items: center;
    }
    .float-btn {
      width: 50px;
      height: 50px;
      border-radius: 50%;
      background: #fff;
      border: 1px solid var(--border-light);
      box-shadow: var(--shadow-md);
      display: flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
      transition: transform var(--transition), box-shadow var(--transition), background var(--transition);
      color: var(--primary);
      font-size: 1.2rem;
      position: relative;
    }
    .float-btn:hover {
      transform: translateY(-3px) scale(1.05);
      box-shadow: var(--shadow-lg);
      background: var(--primary);
      color: #fff;
    }
    .float-btn .float-tooltip {
      display: none;
      position: absolute;
      right: 60px;
      top: 50%;
      transform: translateY(-50%);
      background: #12122a;
      color: #fff;
      font-size: 0.78rem;
      padding: 6px 12px;
      border-radius: 8px;
      white-space: nowrap;
      pointer-events: none;
      font-weight: 500;
    }
    .float-btn:hover .float-tooltip { display: block; }
    .back-top { opacity: 0; visibility: hidden; transition: opacity var(--transition), visibility var(--transition); }
    .back-top.show { opacity: 1; visibility: visible; }

    /* Active nav */
    .nav-links a.active { color: var(--primary); background: rgba(74, 58, 255, 0.06); }

    /* Reveal animation */
    .reveal {
      opacity: 0;
      transform: translateY(30px);
      transition: opacity 0.7s cubic-bezier(0.25, 0.46, 0.45, 0.94), transform 0.7s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    }
    .reveal.visible {
      opacity: 1;
      transform: translateY(0);
    }
    .reveal-delay-1 { transition-delay: 0.08s; }
    .reveal-delay-2 { transition-delay: 0.16s; }
    .reveal-delay-3 { transition-delay: 0.24s; }

    /* Responsive */
    @media (max-width: 1024px) {
      .grid-4 { grid-template-columns: repeat(2, 1fr); }
      .steps { grid-template-columns: repeat(2, 1fr); }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      .testimonial-grid { grid-template-columns: repeat(2, 1fr); }
      .hero-metrics { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 900px) {
      .nav-toggle { display: block; }
      .nav-links {
        display: none;
        flex-direction: column;
        width: 100%;
        padding: 12px 0 6px;
        gap: 0;
        border-top: 1px solid rgba(74, 58, 255, 0.08);
        margin-top: 6px;
      }
      .nav-links.open { display: flex; }
      .nav-links li { display: block; width: 100%; }
      .nav-links a { display: block; padding: 10px 8px; border-radius: 8px; }
      .nav-cta { display: block; text-align: center; margin-top: 6px; }
      .grid-3 { grid-template-columns: repeat(2, 1fr); }
      .grid-2 { grid-template-columns: 1fr; }
      .article-list { grid-template-columns: 1fr; }
      .gallery-grid { grid-template-columns: 1fr; }
    }
    @media (max-width: 640px) {
      .section { padding: 48px 0; }
      .hero { padding: 54px 0 48px; }
      .hero-metrics { grid-template-columns: 1fr 1fr; gap: 10px; }
      .metric-card { padding: 16px 8px; }
      .grid-4 { grid-template-columns: 1fr; }
      .grid-3 { grid-template-columns: 1fr; }
      .steps { grid-template-columns: 1fr; }
      .testimonial-grid { grid-template-columns: 1fr; }
      .form-grid { grid-template-columns: 1fr; }
      .form-wrapper { padding: 26px 18px; }
      .footer-grid { grid-template-columns: 1fr; gap: 26px; }
      .float-actions { right: 12px; bottom: 18px; }
      .float-btn { width: 44px; height: 44px; font-size: 1.05rem; }
      .hero-actions .btn { padding: 12px 24px; font-size: 0.92rem; }
      .compare-table { font-size: 0.82rem; min-width: 620px; }
      .compare-table th, .compare-table td { padding: 12px 14px; }
    }
    @media (max-width: 400px) {
      :root { --container-pad: 14px; }
      .hero-metrics { grid-template-columns: 1fr; }
      .metric-card { padding: 14px; }
    }