:root{--navy:#14285a;--red:#b3172b;--ink:#1d2433;--muted:#5b6475;--bg:#fbfaf7;--card:#fff;--line:#e5e2da}*{box-sizing:border-box}body{color:var(--ink);background:var(--bg);margin:0;font-family:ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,sans-serif;line-height:1.55}a{color:var(--navy)}header.site{background:var(--navy);color:#fff;border-bottom:4px solid var(--red)}header.site .in{align-items:center;gap:12px;max-width:960px;margin:auto;padding:10px 16px;display:flex}header.site img{background:#fff;border-radius:10px;width:52px;height:52px}header.site a{color:#fff;text-decoration:none}header.site .brand{letter-spacing:.02em;font-size:1.1rem;font-weight:800}header.site nav{gap:16px;margin-left:auto;font-size:.95rem;display:flex}main{max-width:960px;margin:auto;padding:24px 16px 64px}h1,h2,h3{color:var(--navy);line-height:1.2}h1{margin:.3em 0;font-size:clamp(1.8rem,5vw,2.6rem)}.card{background:var(--card);border:1px solid var(--line);border-radius:14px;margin:16px 0;padding:20px;box-shadow:0 1px 2px #00000008}.btn{background:var(--red);color:#fff;cursor:pointer;border:0;border-radius:10px;padding:12px 20px;font-size:1rem;font-weight:700;text-decoration:none;display:inline-block}.btn.alt{background:var(--navy)}.btn:disabled{opacity:.6}label{margin:14px 0 6px;font-weight:600;display:block}input,select,textarea{border:1px solid var(--line);background:#fff;border-radius:10px;width:100%;padding:11px;font-size:1rem}.choices{grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:12px;display:grid}.choice{border:2px solid var(--line);cursor:pointer;background:#fff;border-radius:14px;padding:16px;display:block}.choice:has(input:checked){border-color:var(--red);background:#fff5f6}.choice input{width:auto;margin-right:8px}.days{flex-wrap:wrap;gap:8px;display:flex}.days label{border:1px solid var(--line);background:#fff;border-radius:999px;margin:0;padding:6px 12px;font-weight:500}.days input{width:auto;margin-right:4px}.disclaimer{color:var(--muted);border-left:4px solid var(--red);background:#fff;border-radius:6px;margin:16px 0;padding:10px 14px;font-size:.88rem}.pill{color:var(--navy);background:#eef1f8;border-radius:999px;padding:2px 10px;font-size:.8rem;font-weight:600;display:inline-block}.muted{color:var(--muted)}table{border-collapse:collapse;width:100%}td,th{border-bottom:1px solid var(--line);text-align:left;padding:8px}.hero{text-align:center;padding:20px 0}.hero img{width:min(320px,80vw)}.about p{line-height:1.65}.btn.listen{vertical-align:middle;padding:6px 12px;font-size:.85rem}.professor{border-top:5px solid var(--red);border-color:var(--navy)}.prof-log{max-height:520px;margin-bottom:8px;overflow-y:auto}.prof-msg{border-radius:10px;margin:8px 0;padding:10px 12px}.prof-msg.user{background:#eef1f8}.prof-msg.assistant{border:1px solid var(--line);border-left:4px solid var(--red);background:#fff}.prof-msg .listen{margin-top:6px;padding:6px 12px;font-size:.85rem}.kidbar{text-align:center;background:#fff7d6;border-bottom:3px solid #f2c94c;padding:8px 12px;font-weight:600}.kids-grid{grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:12px;display:grid}.kid-card{text-align:center}.avatars{flex-wrap:wrap;gap:8px;display:flex}.avatar{border:2px solid var(--line);cursor:pointer;border-radius:12px;margin:0;padding:6px 10px;font-size:1.6rem;font-weight:400}.avatar:has(input:checked){border-color:var(--red);background:#fff5f6}.avatar input{width:auto}label.check{align-items:flex-start;gap:8px;font-weight:500;display:flex}label.check input{width:auto;margin-top:5px}.topics{grid-template-columns:repeat(auto-fit,minmax(200px,1fr));display:grid}.stats{grid-template-columns:repeat(auto-fit,minmax(170px,1fr));gap:12px;display:grid}.stat{text-align:center;margin:8px 0}.stat b{color:var(--navy);font-size:1.8rem;display:block}.stat span{color:var(--muted);font-size:.9rem}.btn.danger{background:#7a0f1c}footer.site{max-width:960px;color:var(--muted);margin:auto;padding:0 16px 32px;font-size:.9rem}body.kidmode{background:#fffdf5}body.kidmode h1{font-size:2rem}.card.kid{font-size:1.1rem}.pricing-grid{grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:16px;margin:16px 0;display:grid}.price-card{text-align:center}.price-card.best{border:2px solid var(--navy)}.price{color:var(--navy);font-size:2.2rem;font-weight:700}.price span{font-size:1rem;font-weight:400}.helpmsgs{max-height:420px;margin:12px 0;overflow:auto}.helpmsg{background:#f3f5fa;border-radius:10px;margin:8px 0;padding:10px 12px}.helpmsg.user{background:#fff4f4;margin-left:15%}.helpmsg.support{margin-right:15%}.helpmsg b{color:var(--muted);font-size:.8rem;display:block}.chip{border:1px solid var(--line);cursor:pointer;background:#fff;border-radius:999px;margin:2px;padding:4px 10px}.chip.on{background:var(--navy);color:#fff}.small{font-size:.85rem}