:root{color:#18324b;background:#f4fbff;font-family:system-ui,sans-serif;line-height:1.7}*{box-sizing:border-box}body{margin:0}header{background:#fff;border-bottom:1px solid #dcecf5;justify-content:space-between;align-items:center;height:72px;padding:0 max(20px,50% - 550px);display:flex}.brand{color:#147bc1;font-size:1.15rem;font-weight:800;text-decoration:none}nav,footer{flex-wrap:wrap;gap:18px;display:flex}a{color:#176fa8}main{max-width:1000px;margin:auto;padding:48px 20px 90px}.hero{text-align:center;background:linear-gradient(135deg,#fff8dc,#e7f7ff);border-radius:28px;padding:40px 15px}.hero h1{margin:10px;font-size:clamp(2rem,6vw,4rem);line-height:1.2}.eyebrow{color:#ed9412;font-weight:700}.actions{flex-wrap:wrap;justify-content:center;gap:12px;margin:20px 0;display:flex}.primary,.secondary,button{min-height:48px;font:inherit;cursor:pointer;border:0;border-radius:12px;padding:12px 18px;font-weight:700}.primary{color:#fff;background:#167fc4;text-decoration:none}.secondary{color:#18324b;background:#ffc84d;text-decoration:none}button{color:#18324b;background:#e5f1f7}button:focus,a:focus{outline-offset:2px;outline:3px solid #ffad20}.grid{grid-template-columns:repeat(2,1fr);gap:18px;margin:28px 0;display:grid}.grid article,.prose,.game{background:#fff;border:1px solid #dcecf5;border-radius:20px;padding:26px}.game{max-width:760px;margin:auto}.game-top{color:#597287;justify-content:space-between;font-weight:700;display:flex}.mode-switch{gap:8px;margin:18px 0;display:flex}.mode-switch .selected{color:#fff;background:#167fc4}.instruction{background:#fff4c9;border-radius:12px;padding:10px}.numbers{grid-template-columns:repeat(4,1fr);gap:12px;margin:20px 0;display:grid}.numbers button{background:#fff;border:2px solid #b5dced;min-height:88px;font-size:2.2rem}.numbers button.picked{background:#ffc84d;border-color:#d88b00;transform:translateY(-2px)}.expression{overflow-wrap:anywhere;background:#f5f9fb;border:2px dashed #b5dced;border-radius:14px;min-height:80px;padding:18px;font-size:clamp(1.3rem,5vw,2rem)}.keys{grid-template-columns:repeat(4,1fr);gap:8px;margin:14px 0;display:grid}.message{min-height:32px;font-weight:700}.ad{color:#6b7d87;background:#f0f4f6;border:1px dashed #aab9c2;border-radius:12px;place-items:center;min-height:110px;margin:38px 0;font-size:.9rem;display:grid}.prose{max-width:760px;margin:auto}.prose p{white-space:pre-line}footer{border-top:1px solid #dcecf5;max-width:1000px;margin:auto;padding:22px 20px 90px}@media (width<=600px){header{height:auto;padding:16px;display:block}nav{display:none}main{padding:24px 12px 90px}.grid{grid-template-columns:1fr}.numbers{grid-template-columns:repeat(2,1fr)}.game{padding:18px}.hero{padding:28px 12px}}