*,::after,::before{box-sizing:border-box}body{margin:0;font-family:Nunito,sans-serif;background:#fafbff;color:#1a1a2e}.cs-nav{position:sticky;top:0;background:rgba(255,255,255,.97);backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);border-bottom:1.5px solid #ede9fe;padding:10px 24px;display:flex;justify-content:space-between;align-items:center;z-index:100;gap:12px}.cs-logo{font-family:'Baloo 2',cursive;font-weight:900;font-size:22px;text-decoration:none;background:linear-gradient(135deg,#ff6b6b,#ffb830);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;white-space:nowrap;letter-spacing:-.3px}.cs-nav-links{display:flex;align-items:center;gap:8px;flex-wrap:wrap}.cs-btn{border-radius:9999px;padding:7px 18px;font-family:Nunito,sans-serif;font-weight:800;font-size:13px;cursor:pointer;border:none;text-decoration:none;display:inline-flex;align-items:center;gap:5px;transition:opacity .15s,transform .15s;white-space:nowrap;letter-spacing:.1px}.cs-btn:hover{opacity:.85;transform:translateY(-1px)}.cs-btn-primary{background:linear-gradient(135deg,#ff6b6b,#ffb830);color:#fff;box-shadow:0 2px 10px rgba(255,107,107,.28)}.cs-btn-ghost{background:#f3f4f6;color:#374151}.cs-btn-ghost:hover{background:#ede9fe;color:#7c3aed}.cs-breadcrumb{max-width:900px;margin:0 auto;padding:14px 24px 0;font-size:12.5px;color:#9ca3af;font-weight:700;letter-spacing:.2px}.cs-breadcrumb a{color:#a855f7;text-decoration:none;font-weight:700}.cs-breadcrumb a:hover{text-decoration:underline}.cs-hero{text-align:center;padding:52px 24px 36px;max-width:760px;margin:0 auto}.cs-grade-badge{display:inline-block;background:linear-gradient(135deg,#a855f7,#7c3aed);color:#fff;border-radius:999px;padding:5px 20px;font-family:Nunito,sans-serif;font-size:13px;font-weight:800;margin-bottom:18px;letter-spacing:.4px;box-shadow:0 3px 12px rgba(168,85,247,.35)}.cs-hero h1{font-family:'Baloo 2',cursive;font-size:clamp(28px, 5vw, 44px);font-weight:900;color:#1a1a2e;margin:0 0 14px;line-height:1.2;letter-spacing:-.5px}.cs-hero-sub{font-family:Nunito,sans-serif;font-size:16.5px;color:#6b7280;line-height:1.65;margin:0 auto 28px;max-width:580px;font-weight:600}.cs-stats{display:flex;justify-content:center;gap:10px;flex-wrap:wrap;margin-bottom:30px}.cs-stat{background:#fff;border:2px solid #ede9fe;border-radius:999px;padding:7px 18px;font-family:Nunito,sans-serif;font-size:13px;font-weight:800;color:#4c1d95;box-shadow:0 1px 4px rgba(168,85,247,.08)}.cs-cta-row{display:flex;justify-content:center;gap:12px;flex-wrap:wrap}.cs-cta-primary{background:linear-gradient(135deg,#ff6b6b,#ffb830);color:#fff;border:none;border-radius:14px;padding:14px 30px;font-family:Nunito,sans-serif;font-size:16px;font-weight:800;cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;gap:8px;transition:opacity .15s,transform .15s;box-shadow:0 5px 18px rgba(255,107,107,.36);letter-spacing:.1px}.cs-cta-primary:hover{opacity:.9;transform:translateY(-2px)}.cs-cta-secondary{background:#fff;border:2px solid #e5e7eb;color:#374151;border-radius:14px;padding:14px 30px;font-family:Nunito,sans-serif;font-size:16px;font-weight:800;cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;gap:8px;transition:border-color .15s,transform .15s,color .15s}.cs-cta-secondary:hover{border-color:#a855f7;color:#7c3aed;transform:translateY(-2px)}.cs-main{max-width:900px;margin:0 auto;padding:8px 20px 64px}.cs-subjects{display:flex;flex-direction:column;gap:28px}.cs-subject-card{background:#fff;border-radius:22px;padding:28px 28px 20px;box-shadow:0 2px 16px rgba(0,0,0,.06);border:1.5px solid #f0ebff}.cs-subject-header{display:flex;align-items:center;gap:14px;margin-bottom:20px;padding-bottom:16px;border-bottom:1.5px solid #f5f3ff}.cs-subject-emoji{width:52px;height:52px;border-radius:16px;background:linear-gradient(135deg,#ede9fe,#ddd6fe);display:flex;align-items:center;justify-content:center;font-size:26px;line-height:1;flex-shrink:0}.cs-subject-info{flex:1}.cs-subject-name{font-family:'Baloo 2',cursive;font-size:21px;font-weight:900;color:#1a1a2e;line-height:1.2;letter-spacing:-.2px}.cs-subject-count{font-family:Nunito,sans-serif;font-size:13px;color:#9ca3af;font-weight:700;margin-top:3px}.cs-chapters{display:flex;flex-direction:column;gap:6px}.cs-chapter{display:flex;align-items:center;gap:12px;padding:11px 14px;border-radius:14px;background:#fafbff;border:1.5px solid #f0ebff;transition:background .15s,border-color .15s}.cs-chapter:hover{background:#f5f3ff;border-color:#ddd6fe}.cs-ch-num{min-width:36px;height:36px;border-radius:10px;background:#ede9fe;color:#6d28d9;font-family:Nunito,sans-serif;font-weight:800;font-size:12px;display:flex;align-items:center;justify-content:center;flex-shrink:0;letter-spacing:-.2px}.cs-chapter>div:nth-child(2){flex:1;min-width:0}.cs-ch-name{font-family:Nunito,sans-serif;font-weight:800;font-size:14.5px;color:#1a1a2e;line-height:1.3}.cs-ch-topics{font-family:Nunito,sans-serif;font-size:12.5px;color:#9ca3af;line-height:1.4;margin-top:2px;font-weight:600}.cs-ch-right{display:flex;flex-direction:column;align-items:flex-end;gap:4px;flex-shrink:0}.cs-free-badge{background:#dcfce7;color:#15803d;font-family:Nunito,sans-serif;font-size:11.5px;font-weight:800;padding:3px 10px;border-radius:999px;white-space:nowrap;letter-spacing:.3px}.cs-premium-badge{background:#f3e8ff;color:#7c3aed;font-family:Nunito,sans-serif;font-size:11.5px;font-weight:800;padding:3px 10px;border-radius:999px;white-space:nowrap;letter-spacing:.1px}.cs-hub-intro{text-align:center;padding:52px 24px 28px;max-width:760px;margin:0 auto}.cs-hub-intro h1{font-family:'Baloo 2',cursive;font-size:clamp(26px, 5vw, 42px);font-weight:900;color:#1a1a2e;margin:0 0 14px;line-height:1.2;letter-spacing:-.5px}.cs-hub-intro p{font-family:Nunito,sans-serif;font-size:16.5px;color:#6b7280;line-height:1.65;margin:0 auto 32px;max-width:560px;font-weight:600}.cs-grade-grid{max-width:900px;margin:0 auto;padding:0 20px 64px;display:grid;grid-template-columns:repeat(4,1fr);gap:18px}.cs-grade-card{background:#fff;border-radius:20px;padding:22px 18px;box-shadow:0 2px 14px rgba(0,0,0,.07);border:1.5px solid #f0ebff;text-decoration:none;color:inherit;display:flex;flex-direction:column;gap:8px;transition:border-color .15s,transform .15s,box-shadow .15s}.cs-grade-card:hover{border-color:#a855f7;transform:translateY(-4px);box-shadow:0 10px 28px rgba(168,85,247,.15)}.cs-grade-card-emoji{font-size:34px;line-height:1;margin-bottom:2px}.cs-grade-card-name{font-family:'Baloo 2',cursive;font-size:18px;font-weight:900;color:#1a1a2e;line-height:1.2;letter-spacing:-.2px}.cs-grade-card-subjects{font-family:Nunito,sans-serif;font-size:12.5px;color:#6b7280;font-weight:700}.cs-grade-card-meta{display:flex;flex-direction:column;gap:5px;margin-top:4px}.cs-grade-card-chapters{font-family:Nunito,sans-serif;font-size:12.5px;font-weight:700;color:#374151}.cs-grade-card-free{font-family:Nunito,sans-serif;font-size:11.5px;font-weight:800;color:#15803d;background:#dcfce7;border-radius:999px;padding:3px 10px;display:inline-block;align-self:flex-start}.cs-features{background:linear-gradient(135deg,#f5f3ff,#ede9fe);padding:44px 24px;margin-top:40px}.cs-features-inner{max-width:900px;margin:0 auto;display:grid;grid-template-columns:repeat(3,1fr);gap:28px}.cs-feature{text-align:center;background:#fff;border-radius:18px;padding:24px 20px;box-shadow:0 2px 12px rgba(168,85,247,.08)}.cs-feature-emoji{font-size:34px;margin-bottom:10px;line-height:1}.cs-feature-title{font-family:'Baloo 2',cursive;font-size:16px;font-weight:800;color:#1a1a2e;margin-bottom:5px;letter-spacing:-.1px}.cs-feature-sub{font-family:Nunito,sans-serif;font-size:13.5px;color:#6b7280;line-height:1.4;font-weight:600}.cs-grade-nav{background:#fff;border-top:1.5px solid #f0ebff;padding:22px 20px;display:flex;justify-content:center;align-items:center;gap:8px;flex-wrap:wrap}.cs-grade-nav-label{font-family:Nunito,sans-serif;font-weight:800;font-size:12.5px;color:#9ca3af;margin-right:4px;white-space:nowrap;text-transform:uppercase;letter-spacing:.5px}.cs-grade-link{padding:7px 18px;border-radius:999px;font-family:Nunito,sans-serif;font-size:13px;font-weight:800;text-decoration:none;color:#4b5563;background:#f3f4f6;transition:background .15s,color .15s;white-space:nowrap}.cs-grade-link:hover{background:#ede9fe;color:#7c3aed}.cs-grade-link.active{background:linear-gradient(135deg,#a855f7,#7c3aed);color:#fff;box-shadow:0 3px 10px rgba(168,85,247,.3)}.cs-footer{background:#1a1a2e;color:#d1d5db;padding:28px 24px;text-align:center;font-family:Nunito,sans-serif;font-size:14px;font-weight:700;line-height:1.8}.cs-footer a{color:#c084fc;text-decoration:none;font-weight:800}.cs-footer a:hover{color:#e9d5ff}@media (max-width:768px){.cs-features-inner,.cs-grade-grid{grid-template-columns:repeat(2,1fr)}}@media (max-width:600px){.cs-nav{padding:8px 14px}.cs-btn{padding:6px 12px;font-size:12px}.cs-hero{padding:36px 16px 24px}.cs-hero h1{font-size:26px}.cs-main{padding:8px 14px 48px}.cs-subject-card{padding:20px 16px 16px}.cs-subject-name{font-size:18px}.cs-features-inner{grid-template-columns:1fr;gap:14px}.cs-grade-grid{grid-template-columns:repeat(2,1fr);gap:12px}.cs-grade-card{padding:16px 14px}.cs-grade-card-name{font-size:15px}.cs-cta-primary,.cs-cta-secondary{font-size:14.5px;padding:12px 22px}.cs-ch-topics{display:none}}@media (max-width:400px){.cs-grade-grid{grid-template-columns:1fr}}