/* ============ Reset & Variables ============ */
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

    :root {
      --primary: #4F46E5;
      --primary-dark: #4338CA;
      --primary-light: #EEF2FF;
      --accent: #10B981;
      --accent-light: #D1FAE5;
      --gray-50: #F9FAFB;
      --gray-100: #F3F4F6;
      --gray-200: #E5E7EB;
      --gray-300: #D1D5DB;
      --gray-400: #9CA3AF;
      --gray-500: #6B7280;
      --gray-600: #4B5563;
      --gray-700: #374151;
      --gray-800: #1F2937;
      --gray-900: #111827;
      --white: #FFFFFF;
      --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
      --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
      --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
      --shadow-lg: 0 10px 15px rgba(0,0,0,0.1), 0 4px 6px rgba(0,0,0,0.05);
      --shadow-xl: 0 20px 25px rgba(0,0,0,0.1), 0 10px 10px rgba(0,0,0,0.04);
      --radius: 12px;
      --radius-lg: 16px;
      --radius-xl: 24px;
      --transition: 0.2s ease;
      --max-width: 1200px;
    }

    html { scroll-behavior: smooth; font-size: 16px; }

    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
      color: var(--gray-800);
      background: var(--white);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

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


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

    .container { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }

    /* ============ Header ============ */
    .header {
      position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
      background: rgba(255,255,255,0.95); backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--gray-200);
      transition: box-shadow var(--transition);
    }
    .header.scrolled { box-shadow: var(--shadow-md); }

    .header-inner {
      display: flex; align-items: center; justify-content: space-between;
      height: 72px; max-width: var(--max-width); margin: 0 auto; padding: 0 24px;
    }

    .logo { display: flex; align-items: center; gap: 10px; font-size: 1.5rem; font-weight: 800; color: var(--gray-900); }
    .logo-icon { width: 40px; height: 40px; background: linear-gradient(135deg, var(--primary), #7C3AED); border-radius: 10px; display: flex; align-items: center; justify-content: center; color: white; font-size: 1.25rem; font-weight: 800; }

    .nav { display: flex; align-items: center; gap: 32px; }
    .nav a { color: var(--gray-600); font-size: 0.95rem; font-weight: 500; transition: color var(--transition); }
    .nav a:hover { color: var(--primary); }

    .btn {
      display: inline-flex; align-items: center; justify-content: center; gap: 8px;
      padding: 12px 28px; border-radius: 10px; font-size: 0.95rem; font-weight: 600;
      cursor: pointer; border: none; transition: all var(--transition); white-space: nowrap;
    }
    .btn-primary { background: var(--primary); color: white; }
    .btn-outline { background: transparent; color: var(--primary); border: 2px solid var(--primary); }
    .btn-lg { padding: 16px 40px; font-size: 1.1rem; border-radius: 12px; }
    .btn-white { background: white; color: var(--primary); }


    .mobile-menu-btn { display: none; background: none; border: none; cursor: pointer; padding: 8px; color: var(--gray-700); }

    /* ============ Hero ============ */
    .hero {
      padding: 100px 0 100px;
      background: linear-gradient(180deg, var(--primary-light) 0%, var(--white) 100%);
      text-align: center;
      overflow: hidden;
    }
    .hero-badge {
      display: inline-flex; align-items: center; gap: 8px;
      background: white; border: 1px solid var(--gray-200); border-radius: 100px;
      padding: 6px 20px; font-size: 0.875rem; color: var(--gray-600); margin-bottom: 32px;
      box-shadow: var(--shadow-sm);
    }
    .hero-badge .dot { width: 8px; height: 8px; background: var(--accent); border-radius: 50%; animation: pulse 2s infinite; }
    @keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.4; } }

    .hero h1 {
      font-size: clamp(2.5rem, 5vw, 3.75rem);
      font-weight: 800; color: var(--gray-900); line-height: 1.2;
      margin-bottom: 24px; letter-spacing: -0.02em;
    }
    .hero h1 .highlight {
      background: linear-gradient(135deg, var(--primary), #7C3AED);
      -webkit-background-clip: text; -webkit-text-fill-color: transparent;
      background-clip: text;
    }

    .hero-desc {
      font-size: 1.2rem; color: var(--gray-500); max-width: 680px;
      margin: 0 auto 40px; line-height: 1.8;
    }

    .hero-actions { display: flex; align-items: center; justify-content: center; gap: 16px; flex-wrap: wrap; }

    /* ============ Section Common ============ */
    .section { padding: 100px 0; }
    .section-gray { background: var(--gray-50); }
    .section-header { text-align: center; margin-bottom: 64px; }
    .section-label {
      display: inline-block; font-size: 0.875rem; font-weight: 600; color: var(--primary);
      background: var(--primary-light); padding: 6px 16px; border-radius: 100px;
      margin-bottom: 16px; letter-spacing: 0.05em; text-transform: uppercase;
    }
    .section-header h2 { font-size: clamp(2rem, 4vw, 2.75rem); font-weight: 800; color: var(--gray-900); margin-bottom: 16px; }
    .section-header p { font-size: 1.1rem; color: var(--gray-500); max-width: 600px; margin: 0 auto; }

    /* ============ Features ============ */
    .features-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; }

    .feature-card {
      background: white; border-radius: var(--radius-lg); padding: 40px 32px;
      border: 1px solid var(--gray-200); transition: all 0.3s ease;
      position: relative; overflow: hidden;
    }
    .feature-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: var(--primary-light); }
    .feature-card::before {
      content: ''; position: absolute; top: 0; left: 0; right: 0; height: 4px;
      background: linear-gradient(90deg, var(--primary), #7C3AED);
      opacity: 0; transition: opacity 0.3s ease;
    }
    .feature-card:hover::before { opacity: 1; }

    .feature-icon {
      width: 56px; height: 56px; border-radius: 14px;
      display: flex; align-items: center; justify-content: center;
      font-size: 1.5rem; margin-bottom: 24px;
    }
    .feature-icon.purple { background: var(--primary-light); color: var(--primary); }
    .feature-icon.green { background: var(--accent-light); color: var(--accent); }
    .feature-icon.orange { background: #FFF7ED; color: #F97316; }
    .feature-icon.blue { background: #EFF6FF; color: #3B82F6; }
    .feature-icon.pink { background: #FDF2F8; color: #EC4899; }
    .feature-icon.cyan { background: #ECFEFF; color: #06B6D4; }

    .feature-card h3 { font-size: 1.2rem; font-weight: 700; color: var(--gray-900); margin-bottom: 12px; }
    .feature-card p { font-size: 0.95rem; color: var(--gray-500); line-height: 1.7; }

    /* ============ How It Works ============ */
    .steps-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 32px; }

    .step-card { text-align: center; position: relative; }
    .step-card:not(:last-child)::after {
      content: ''; position: absolute; top: 36px; right: -28px;
      width: 40px; height: 2px; background: var(--gray-200);
    }
    .step-number {
      width: 72px; height: 72px; border-radius: 50%;
      background: linear-gradient(135deg, var(--primary), #7C3AED);
      color: white; display: flex; align-items: center; justify-content: center;
      font-size: 1.5rem; font-weight: 800; margin: 0 auto 24px;
      box-shadow: 0 8px 20px rgba(79,70,229,0.3);
    }
    .step-card h3 { font-size: 1.1rem; font-weight: 700; color: var(--gray-900); margin-bottom: 8px; }
    .step-card p { font-size: 0.9rem; color: var(--gray-500); line-height: 1.6; }

    /* ============ Templates ============ */
    .templates-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }

    .template-card {
      border-radius: var(--radius-lg); overflow: hidden;
      border: 1px solid var(--gray-200); transition: all 0.3s ease;
      background: white;
    }
    .template-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }

    .template-preview {
      height: 160px; display: flex; align-items: center; justify-content: center;
      color: white; font-weight: 700; font-size: 1.25rem;
    }
    .template-preview.business { background: linear-gradient(135deg, #1e3a5f, #2d5a87); }
    .template-preview.tech { background: linear-gradient(135deg, #0f0c29, #302b63, #24243e); }
    .template-preview.edu { background: linear-gradient(135deg, #11998e, #38ef7d); }
    .template-preview.marketing { background: linear-gradient(135deg, #fc4a1a, #f7b733); }
    .template-preview.plan { background: linear-gradient(135deg, #4e54c8, #8f94fb); }
    .template-preview.report { background: linear-gradient(135deg, #232526, #414345); }
    .template-preview.product { background: linear-gradient(135deg, #667eea, #764ba2); }
    .template-preview.data { background: linear-gradient(135deg, #00b4db, #0083b0); }

    .template-info { padding: 16px; }
    .template-info h4 { font-size: 0.95rem; font-weight: 700; color: var(--gray-900); margin-bottom: 4px; }
    .template-info span { font-size: 0.8rem; color: var(--gray-400); }

    /* ============ Tutorials ============ */
    .tutorials-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; }

    .tutorial-card {
      background: white; border-radius: var(--radius-lg); overflow: hidden;
      border: 1px solid var(--gray-200); transition: all 0.3s ease;
    }
    .tutorial-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }

    .tutorial-video {
      position: relative; width: 100%; padding-top: 56.25%; background: var(--gray-900);
    }
    .tutorial-video iframe {
      position: absolute; top: 0; left: 0; width: 100%; height: 100%; border: none;
    }
    .tutorial-video .play-overlay {
      position: absolute; inset: 0; display: flex; align-items: center; justify-content: center;
      background: rgba(0,0,0,0.3); cursor: pointer; transition: background 0.3s ease;
    }
    .tutorial-video .play-overlay:hover { background: rgba(0,0,0,0.1); }
    .tutorial-video .play-icon {
      width: 64px; height: 64px; border-radius: 50%;
      background: rgba(255,255,255,0.9); display: flex; align-items: center; justify-content: center;
      transition: transform 0.3s ease;
    }
    .tutorial-video .play-overlay:hover .play-icon { transform: scale(1.1); }
    .tutorial-video .play-icon::after {
      content: ''; width: 0; height: 0;
      border-left: 20px solid var(--primary); border-top: 12px solid transparent; border-bottom: 12px solid transparent;
      margin-left: 4px;
    }

    .tutorial-info { padding: 20px; }
    .tutorial-info h4 { font-size: 1rem; font-weight: 700; color: var(--gray-900); margin-bottom: 8px; }
    .tutorial-info p { font-size: 0.85rem; color: var(--gray-500); line-height: 1.6; }
    .tutorial-meta { display: flex; align-items: center; gap: 16px; margin-top: 12px; font-size: 0.8rem; color: var(--gray-400); }
    .tutorial-meta span { display: flex; align-items: center; gap: 4px; }

    /* ============ FAQ ============ */
    .faq-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }

    .faq-item {
      background: white; border-radius: var(--radius-lg); padding: 28px;
      border: 1px solid var(--gray-200); transition: all 0.3s ease;
    }
    .faq-item:hover { border-color: var(--primary-light); box-shadow: var(--shadow-sm); }
    .faq-item h3 { font-size: 1.05rem; font-weight: 700; color: var(--gray-900); margin-bottom: 12px; }
    .faq-item p { font-size: 0.9rem; color: var(--gray-500); line-height: 1.7; }

    /* ============ CTA ============ */
    .cta {
      background: linear-gradient(135deg, var(--primary), #7C3AED);
      color: white; text-align: center; padding: 100px 0;
      position: relative; overflow: hidden;
    }
    .cta::before {
      content: ''; position: absolute; inset: 0;
      background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
    }
    .cta > * { position: relative; z-index: 1; }
    .cta h2 { font-size: clamp(2rem, 4vw, 2.75rem); font-weight: 800; margin-bottom: 16px; }
    .cta p { font-size: 1.1rem; opacity: 0.9; max-width: 600px; margin: 0 auto 40px; line-height: 1.8; }
    .cta .btn-white { font-size: 1.1rem; padding: 16px 48px; }

    /* ============ Footer ============ */
    .footer { background: var(--gray-900); color: var(--gray-400); padding: 64px 0 32px; }

    .footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 48px; margin-bottom: 48px; }

    .footer-brand .logo { color: white; margin-bottom: 16px; }
    .footer-brand p { font-size: 0.9rem; line-height: 1.7; margin-bottom: 20px; }

    .footer h4 { color: white; font-size: 0.95rem; font-weight: 700; margin-bottom: 20px; }
    .footer-links { list-style: none; }
    .footer-links li { margin-bottom: 12px; }
    .footer-links a { color: var(--gray-400); font-size: 0.9rem; transition: color var(--transition); }
    .footer-links a:hover { color: white; }

    .footer-bottom {
      border-top: 1px solid var(--gray-700);
      padding-top: 32px; text-align: center; font-size: 0.85rem;
      display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 16px;
    }

    /* ============ Mobile Nav ============ */
    .mobile-nav {
      display: none; position: fixed; top: 72px; left: 0; right: 0; bottom: 0;
      background: white; z-index: 999; padding: 24px; flex-direction: column; gap: 8px;
      overflow-y: auto;
    }
    .mobile-nav.active { display: flex; }
    .mobile-nav a {
      display: block; padding: 16px 20px; font-size: 1.05rem; font-weight: 500;
      color: var(--gray-700); border-radius: var(--radius); transition: all var(--transition);
    }

    .mobile-nav .btn { margin-top: 16px; text-align: center; }

    /* ============ Responsive ============ */
    @media (max-width: 1024px) {
      .features-grid { grid-template-columns: 1fr 1fr; }
      .steps-grid { grid-template-columns: 1fr 1fr; }
      .step-card:not(:last-child)::after { display: none; }
      .templates-grid { grid-template-columns: 1fr 1fr; }
      .tutorials-grid { grid-template-columns: 1fr; max-width: 500px; margin: 0 auto; }
      .faq-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }

    @media (max-width: 768px) {
      .nav { display: none; }
      .mobile-menu-btn { display: block; }
      .features-grid { grid-template-columns: 1fr; }
      .steps-grid { grid-template-columns: 1fr; }
      .templates-grid { grid-template-columns: 1fr 1fr; }
      .hero { padding: 60px 0 60px; }
      .section { padding: 64px 0; }
      .footer-grid { grid-template-columns: 1fr; }
      .footer-bottom { flex-direction: column; text-align: center; }
    }
    
    img.logo {
        width: 36px;
        border-radius: 18px;
    }