@import"https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&display=swap";:root{--bg-primary: #f6f5f4;--bg-secondary: #ffffff;--bg-tertiary: #ebeae9;--bg-hover: #efeeed;--text-primary: #37352f;--text-secondary: #6b6b6b;--text-tertiary: #9b9b9b;--accent: #0075de;--accent-hover: #0066c4;--accent-light: #e8f3fd;--accent-dark: #0055a8;--green: #2e7d32;--green-light: #e8f5e9;--orange: #e65100;--orange-light: #fff3e0;--red: #c62828;--red-light: #ffebee;--purple: #6a1b9a;--purple-light: #f3e5f5;--border: #e3e2e0;--border-light: #efeeed;--radius: 8px;--radius-lg: 12px;--shadow-sm: 0 1px 3px rgba(0,0,0,.04);--shadow-md: 0 4px 12px rgba(0,0,0,.06);--shadow-lg: 0 8px 24px rgba(0,0,0,.08);--max-width: 1200px;--header-height: 64px}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}html{font-size:16px;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}body{font-family:Inter,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;background:var(--bg-primary);color:var(--text-primary);line-height:1.6;min-height:100vh}img,svg{display:block;max-width:100%}a{color:var(--accent);text-decoration:none;transition:color .15s ease}a:hover{color:var(--accent-hover);text-decoration:underline}.container{max-width:var(--max-width);margin:0 auto;padding:0 24px}.header{background:var(--bg-secondary);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:100;height:var(--header-height)}.header-inner{display:flex;align-items:center;justify-content:space-between;height:100%;max-width:var(--max-width);margin:0 auto;padding:0 24px}.logo{font-size:1.25rem;font-weight:700;color:var(--text-primary);text-decoration:none;display:flex;align-items:center;gap:8px}.logo:hover{color:var(--text-primary);text-decoration:none}.logo-icon{width:32px;height:32px;background:var(--accent);border-radius:6px;display:flex;align-items:center;justify-content:center;color:#fff;font-weight:800;font-size:.9rem}.nav{display:flex;align-items:center;gap:24px}.nav a{color:var(--text-secondary);font-size:.875rem;font-weight:500;text-decoration:none;padding:6px 0;position:relative}.nav a:hover{color:var(--text-primary);text-decoration:none}.nav a.active{color:var(--accent)}.nav a.active:after{content:"";position:absolute;bottom:-2px;left:0;right:0;height:2px;background:var(--accent);border-radius:1px}.nav-premium{background:var(--accent);color:#fff!important;padding:4px 14px!important;border-radius:6px;font-weight:600!important;font-size:.8125rem!important}.nav-premium:hover{background:var(--accent-hover)!important;color:#fff!important;text-decoration:none!important}.nav-premium.active{background:var(--accent-dark)!important}.nav-grades{display:flex;gap:4px}.nav-grade-btn{display:inline-flex;align-items:center;justify-content:center;width:36px;height:36px;border-radius:6px;font-size:.8rem;font-weight:600;color:var(--text-secondary);background:transparent;transition:all .15s ease}.nav-grade-btn:hover{background:var(--bg-hover);color:var(--text-primary);text-decoration:none}.nav-grade-btn.active{background:var(--accent-light);color:var(--accent)}.hero{padding:80px 0 60px;text-align:center}.hero h1{font-size:2.75rem;font-weight:800;line-height:1.15;letter-spacing:-.03em;margin-bottom:16px;color:var(--text-primary)}.hero h1 span{color:var(--accent)}.hero p{font-size:1.125rem;color:var(--text-secondary);max-width:640px;margin:0 auto 32px;line-height:1.65}.hero-actions{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}.btn{display:inline-flex;align-items:center;gap:8px;font-family:Inter,sans-serif;font-size:.9375rem;font-weight:600;padding:12px 28px;border-radius:var(--radius);border:none;cursor:pointer;transition:all .15s ease;text-decoration:none}.btn:hover{text-decoration:none}.btn-primary{background:var(--accent);color:#fff}.btn-primary:hover{background:var(--accent-hover);color:#fff}.btn-secondary{background:var(--bg-secondary);color:var(--text-primary);border:1px solid var(--border)}.btn-secondary:hover{background:var(--bg-hover);border-color:var(--text-tertiary);color:var(--text-primary)}.btn-sm{font-size:.8125rem;padding:8px 16px}.grade-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(340px,1fr));gap:16px;padding:40px 0}.grade-card{background:var(--bg-secondary);border:1px solid var(--border);border-radius:var(--radius-lg);padding:24px;transition:all .15s ease;text-decoration:none;display:block}.grade-card:hover{border-color:var(--accent);box-shadow:var(--shadow-md);text-decoration:none}.grade-card-header{display:flex;align-items:center;gap:12px;margin-bottom:12px}.grade-badge{width:40px;height:40px;border-radius:8px;display:flex;align-items:center;justify-content:center;font-size:1rem;font-weight:700;color:#fff;flex-shrink:0}.grade-card h3{font-size:1.125rem;font-weight:600;color:var(--text-primary)}.grade-card p{font-size:.875rem;color:var(--text-secondary);line-height:1.5}.grade-card-meta{display:flex;gap:16px;margin-top:12px;font-size:.8125rem;color:var(--text-tertiary)}.section{padding:60px 0}.section-header{text-align:center;margin-bottom:40px}.section-header h2{font-size:1.75rem;font-weight:700;margin-bottom:8px}.section-header p{color:var(--text-secondary);font-size:1rem}.topic-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:12px}.topic-card{background:var(--bg-secondary);border:1px solid 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ease}.worksheet-item:hover{border-color:var(--accent)}.worksheet-info{display:flex;align-items:center;gap:12px}.worksheet-icon{width:32px;height:32px;border-radius:4px;display:flex;align-items:center;justify-content:center;font-size:.9rem;flex-shrink:0}.worksheet-name{font-size:.9375rem;font-weight:500}.worksheet-meta{font-size:.8125rem;color:var(--text-tertiary)}.difficulty{display:inline-flex;align-items:center;gap:4px;font-size:.75rem;font-weight:600;padding:2px 8px;border-radius:4px}.difficulty-easy{background:var(--green-light);color:var(--green)}.difficulty-medium{background:var(--orange-light);color:var(--orange)}.difficulty-hard{background:var(--red-light);color:var(--red)}.features{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:24px;padding:40px 0}.feature-card{text-align:center;padding:32px 20px}.feature-icon{width:56px;height:56px;border-radius:12px;display:flex;align-items:center;justify-content:center;font-size:1.5rem;margin:0 auto 16px}.feature-card h3{font-size:1.0625rem;font-weight:600;margin-bottom:8px}.feature-card p{font-size:.875rem;color:var(--text-secondary);line-height:1.55}.footer{background:var(--bg-secondary);border-top:1px solid var(--border);padding:40px 0;margin-top:60px}.footer-inner{max-width:var(--max-width);margin:0 auto;padding:0 24px;display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:16px}.footer-links{display:flex;gap:20px;font-size:.875rem}.footer-links a{color:var(--text-tertiary)}.footer-links a:hover{color:var(--text-primary)}.footer-copy{font-size:.8125rem;color:var(--text-tertiary)}.breadcrumb{display:flex;align-items:center;gap:8px;font-size:.8125rem;color:var(--text-tertiary);padding:20px 0}.breadcrumb a{color:var(--text-tertiary)}.breadcrumb a:hover{color:var(--accent)}.breadcrumb-sep{color:var(--border)}.page-header{padding:40px 0 24px}.page-header h1{font-size:2rem;font-weight:700;margin-bottom:8px}.page-header p{color:var(--text-secondary);font-size:1rem;max-width:600px}.pdf-preview{background:var(--bg-secondary);border:1px solid var(--border);border-radius:var(--radius-lg);padding:32px;margin:24px 0;text-align:center}.pdf-placeholder{width:100%;max-width:400px;height:500px;background:var(--bg-tertiary);border-radius:var(--radius);display:flex;flex-direction:column;align-items:center;justify-content:center;margin:0 auto;color:var(--text-tertiary);font-size:.875rem;gap:12px}.pdf-actions{display:flex;gap:12px;justify-content:center;margin-top:20px}.related-section{margin-top:48px}.related-section h3{font-size:1.125rem;font-weight:600;margin-bottom:16px}.testimonial{background:var(--bg-secondary);border:1px solid var(--border);border-radius:var(--radius-lg);padding:24px}.testimonial-text{font-size:.9375rem;line-height:1.6;color:var(--text-secondary);font-style:italic;margin-bottom:16px}.testimonial-author{display:flex;align-items:center;gap:10px}.testimonial-avatar{width:36px;height:36px;border-radius:50%;background:var(--bg-tertiary);display:flex;align-items:center;justify-content:center;font-weight:600;font-size:.875rem}.testimonial-name{font-size:.875rem;font-weight:600}.testimonial-role{font-size:.8125rem;color:var(--text-tertiary)}.pricing-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:20px;padding:40px 0}.pricing-card{background:var(--bg-secondary);border:1px solid var(--border);border-radius:var(--radius-lg);padding:32px 24px;text-align:center;position:relative}.pricing-card.featured{border-color:var(--accent);box-shadow:var(--shadow-md)}.pricing-badge{position:absolute;top:-12px;left:50%;transform:translate(-50%);background:var(--accent);color:#fff;font-size:.75rem;font-weight:600;padding:4px 16px;border-radius:20px}.pricing-card h3{font-size:1.125rem;font-weight:600;margin-bottom:8px}.pricing-price{font-size:2.5rem;font-weight:800;color:var(--text-primary);margin-bottom:4px}.pricing-desc{font-size:.875rem;color:var(--text-tertiary);margin-bottom:20px}.pricing-features{list-style:none;text-align:left;margin-bottom:24px}.pricing-features li{padding:8px 0;font-size:.875rem;display:flex;align-items:center;gap:8px;border-bottom:1px solid var(--border-light)}.pricing-features li:last-child{border-bottom:none}.pricing-features li:before{content:"✓";color:var(--green);font-weight:700}.cta-section{background:var(--accent);color:#fff;border-radius:var(--radius-lg);padding:60px 40px;text-align:center;margin:60px 0}.cta-section h2{font-size:1.75rem;font-weight:700;margin-bottom:12px}.cta-section p{font-size:1rem;opacity:.9;margin-bottom:24px;max-width:500px;margin-left:auto;margin-right:auto}.cta-section .btn-primary{background:#fff;color:var(--accent)}.cta-section .btn-primary:hover{background:var(--bg-primary)}@media(max-width:768px){.hero h1{font-size:2rem}.hero p{font-size:1rem}.grade-grid,.topic-grid,.features,.pricing-grid{grid-template-columns:1fr}.nav-grades{display:none}.cta-section{padding:40px 24px}.footer-inner{flex-direction:column;text-align:center}}@media(max-width:480px){.hero{padding:48px 0 40px}.hero h1{font-size:1.625rem}.page-header h1{font-size:1.5rem}.container,.header-inner{padding:0 16px}}