:root{font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;color:#e5e7eb;background:#0b1220;font-synthesis:none;text-rendering:optimizeLegibility}*{box-sizing:border-box}body{margin:0;min-width:320px;min-height:100vh;background:radial-gradient(circle at top,#17223a,#0b1220 52%,#070b12)}button{font:inherit}.app-shell{min-height:100vh;display:grid;place-items:center;padding:20px}.game-card{width:min(100%,680px);padding:clamp(18px,4vw,32px);border:1px solid rgba(148,163,184,.2);border-radius:20px;background:#0f172aeb;box-shadow:0 24px 70px #00000047}.game-header{text-align:center}.eyebrow{margin:0 0 6px;color:#94a3b8;font-size:.76rem;font-weight:700;letter-spacing:.14em;text-transform:uppercase}h1{margin:0;font-size:clamp(2rem,8vw,3.3rem);letter-spacing:.08em}.status{min-height:1.5em;margin:12px 0 0;font-weight:700;color:#f8fafc}.scoreboard{display:flex;justify-content:center;flex-wrap:wrap;gap:10px 18px;margin:22px 0 18px;color:#cbd5e1}.board{width:min(100%,560px);margin:0 auto;display:grid;grid-template-columns:repeat(9,1fr);gap:clamp(2px,.7vw,5px);padding:clamp(5px,1vw,8px);border-radius:14px;background:#07101d;touch-action:manipulation}.cell{aspect-ratio:1;min-width:0;border:0;border-radius:clamp(4px,1.5vw,9px);background:#273449;box-shadow:inset 0 -2px #0000002e;cursor:pointer;transition:transform 90ms ease,filter 90ms ease,background 90ms ease;-webkit-tap-highlight-color:transparent}.cell:focus-visible{outline:3px solid #f8fafc;outline-offset:2px}.cell:active:not(:disabled){transform:scale(.95)}.cell--blue{background:#2563eb}.cell--red{background:#dc2626}.cell--invalid{filter:brightness(1.45)}.cell:disabled{cursor:default;opacity:1}.reset-button{display:block;margin:22px auto 0;min-height:46px;padding:0 22px;border:1px solid #475569;border-radius:10px;color:#f8fafc;background:#1e293b;font-weight:700;cursor:pointer}.reset-button:focus-visible{outline:3px solid #60a5fa;outline-offset:3px}@media(hover:hover)and (pointer:fine){.cell:hover:not(:disabled){filter:brightness(1.15)}.reset-button:hover{background:#334155}}@media(max-width:420px){.app-shell{padding:10px}.game-card{padding:16px 12px 18px;border-radius:14px}.scoreboard{font-size:.92rem}}.mode-info{margin:8px 0 0;color:#cbd5e1;font-size:.92rem}.mode-control{display:flex;align-items:center;justify-content:center;gap:10px;margin:14px auto 0;color:#cbd5e1;font-weight:700}.mode-control select{min-height:40px;padding:0 10px;border:1px solid #475569;border-radius:8px;color:#f8fafc;background:#1e293b;font:inherit}