*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;font-family:Inter,system-ui,-apple-system,Segoe UI,Arial,sans-serif;background:#f5f7ff;color:#1f2440;line-height:1.6}.site-header{position:sticky;top:0;z-index:20;background:rgba(255,255,255,.94);backdrop-filter:blur(12px);border-bottom:1px solid #e8e8f5;padding:12px clamp(16px,4vw,70px);display:flex;justify-content:space-between;align-items:center}.brand{display:flex;align-items:center;gap:10px}.brand-mark{width:42px;height:42px;border-radius:13px;background:linear-gradient(135deg,#6c5ce7,#00b894);color:white;display:grid;place-items:center;font-size:25px;font-weight:900;box-shadow:0 8px 20px #6c5ce733}.brand strong{display:block;font-size:20px}.brand span{font-size:11px;color:#737894}.site-header nav{display:flex;gap:20px}.site-header a{color:#454967;text-decoration:none;font-weight:700;font-size:14px}.hero{max-width:1200px;margin:25px auto;padding:55px 6%;border-radius:30px;background:linear-gradient(135deg,#171d49,#5146b8);color:#fff;display:flex;justify-content:space-between;align-items:center;overflow:hidden;box-shadow:0 20px 50px #35308b30}.hero-copy{max-width:720px}.badge,.eyebrow{font-size:11px;font-weight:900;letter-spacing:1.3px;color:#00d8a2}.hero h1{font-size:clamp(34px,6vw,62px);line-height:1.05;margin:14px 0}.hero h1 span{display:block;color:#a9ffec}.hero p{font-size:18px;color:#e4e5ff;max-width:700px}.hero-buttons{display:flex;gap:12px;flex-wrap:wrap;margin-top:25px}.math-art{width:340px;height:280px;position:relative;display:grid;place-items:center}.notebook{width:220px;height:175px;background:#fff;color:#292b54;border-radius:20px;transform:rotate(-5deg);box-shadow:0 20px 45px #0004;padding:28px;display:flex;flex-direction:column;justify-content:center}.notebook span{color:#6c5ce7;font-size:18px}.notebook b{font-size:30px}.notebook small{color:#7d8097}.bubble{position:absolute;background:#ffda79;color:#333;border-radius:18px;padding:12px 17px;font-weight:900;box-shadow:0 8px 20px #0002;animation:float 3s ease-in-out infinite}.b1{top:15px;left:10px}.b2{right:5px;top:70px;background:#81ecec}.b3{bottom:12px;left:35px;background:#fd79a8;color:#fff}@keyframes float{50%{transform:translateY(-8px) rotate(2deg)}}.panel,.content-section{max-width:1200px;margin:24px auto;padding:clamp(20px,4vw,40px);background:#fff;border-radius:25px;box-shadow:0 10px 35px #3331}.panel-title,.status-row{display:flex;justify-content:space-between;align-items:center;gap:15px}.panel-title h2,.section-heading h2{margin:3px 0 15px;font-size:30px}.score-pill{background:#f0edff;border-radius:20px;padding:10px 16px;color:#5c4bc7}.controls{display:flex;gap:10px;flex-wrap:wrap;align-items:end}.controls label{font-weight:800;font-size:12px;color:#62667d;display:flex;flex-direction:column;gap:5px}.controls select{padding:12px 30px 12px 12px;border:1px solid #dddff0;border-radius:12px;background:#fff;font-size:15px}.primary,.secondary{border:0;border-radius:12px;padding:12px 16px;font-weight:900;cursor:pointer;transition:.2s}.primary{background:#6c5ce7;color:#fff}.secondary{background:#edf0fb;color:#353a59}.primary:hover,.secondary:hover{transform:translateY(-2px)}.status-row{margin:22px 0}.timer{font-size:18px;white-space:nowrap}.progress-wrap{display:flex;align-items:center;gap:10px;width:min(650px,75%)}.progress{height:12px;background:#eceef7;border-radius:99px;overflow:hidden;flex:1}.progress div{height:100%;width:0;background:linear-gradient(90deg,#6c5ce7,#00b894);transition:.35s}.progress-wrap span{font-size:12px;font-weight:800;color:#72768c}.notice{background:#fff8db;border-left:5px solid #fdcb6e;padding:12px 15px;border-radius:12px;margin:15px 0}.questions{display:grid;grid-template-columns:repeat(2,1fr);gap:15px}.question-card{border:1px solid #e8e9f3;border-radius:18px;padding:20px;background:#fbfcff;transition:.25s}.question-card.correct{border-color:#00b894;background:#effff9;animation:correct .45s}.question-card.wrong{border-color:#e17055;background:#fff5f2;animation:wrong .35s}@keyframes correct{50%{transform:scale(1.02)}}@keyframes wrong{25%,75%{transform:translateX(-5px)}50%{transform:translateX(5px)}}.q-number{color:#6c5ce7;font-size:12px;font-weight:900}.q-text{font-size:21px;font-weight:850;margin:8px 0 14px}.answer-row{display:flex;gap:8px}.answer-row input{min-width:0;flex:1;border:2px solid #dfe1ed;border-radius:12px;padding:13px;font-size:18px}.answer-row input.correct-input{border-color:#00b894;background:#e9fff8;color:#087d65}.answer-row input.wrong-input{border-color:#e17055;background:#fff0ed;color:#b33d27}.check-btn{border:0;border-radius:12px;background:#303657;color:#fff;padding:10px 14px;font-weight:900;cursor:pointer}.feedback{font-size:13px;font-weight:800;margin-top:9px;min-height:20px}.answer-btn{display:none;margin-top:7px;border:0;background:#ffeaa7;color:#5a4510;border-radius:9px;padding:7px 10px;font-weight:800;cursor:pointer}.result{margin-top:25px;padding:24px;border-radius:20px;background:linear-gradient(135deg,#eafff8,#f0edff);text-align:center}.result h3{font-size:30px;margin:0}.hidden{display:none}.learn-grid{display:grid;grid-template-columns:1fr 1fr;gap:35px}.learn-grid h3{color:#5146b8;margin-bottom:5px}.learn-grid mark{background:#fff0a8;padding:2px 5px;border-radius:5px}.learn-grid li{margin:9px 0}.formula-box{background:#1e2348;color:#fff;border-radius:17px;padding:18px;font-family:Georgia,serif;font-size:18px;display:grid;gap:9px}.tip-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}.tip-grid>div{padding:18px;border-radius:16px;background:#f5f6ff;border:1px solid #e7e8f5}.faq details{padding:15px 0;border-bottom:1px solid #eee}.faq summary{cursor:pointer;font-weight:900}.faq p{color:#666b82}footer{padding:30px 6%;background:#191e42;color:#fff;display:flex;justify-content:space-between;gap:15px;flex-wrap:wrap;margin-top:30px}@media(max-width:800px){.site-header nav{display:none}.hero{margin:10px;padding:35px 22px}.math-art{display:none}.questions,.learn-grid{grid-template-columns:1fr}.tip-grid{grid-template-columns:1fr 1fr}.panel,.content-section{margin:12px;border-radius:18px}.panel-title{align-items:flex-start}.status-row{align-items:flex-start;flex-direction:column}.progress-wrap{width:100%}.controls>*{width:100%}.controls label select{width:100%}.primary,.secondary{width:100%}.answer-row{flex-direction:column}.check-btn{width:100%}.q-text{font-size:19px}}@media(max-width:460px){.tip-grid{grid-template-columns:1fr}.hero h1{font-size:38px}.hero p{font-size:16px}.panel-title{flex-direction:column}.score-pill{align-self:stretch;text-align:center}}
