:root{
  --bg:#07111f;
  --panel:#0d1d31;
  --line:#203956;
  --text:#eef7ff;
  --muted:#9eb3c8;
  --accent:#67e8f9;
}
*{box-sizing:border-box}
html,body{margin:0;width:100%;height:100%;overflow:hidden;background:var(--bg);color:var(--text);font-family:Arial,sans-serif}
body{display:grid;place-items:center}
button{font:inherit}
.game-shell{width:100%;height:100%;max-width:760px;padding:10px;display:grid;grid-template-rows:auto 1fr auto;gap:10px}
.hud{display:grid;grid-template-columns:repeat(3,1fr);gap:8px}
.stat{background:var(--panel);border:1px solid var(--line);border-radius:14px;text-align:center;padding:9px}
.stat span{display:block;color:var(--muted);font-size:.8rem}
.stat strong{display:block;font-size:1.45rem;margin-top:3px}
.board-wrap{position:relative;min-height:0;display:grid;place-items:center}
.board{width:min(100%,560px);display:grid;grid-template-columns:repeat(4,1fr);gap:10px}
.card{aspect-ratio:1;border:0;border-radius:16px;background:#142a45;cursor:pointer;position:relative;transform-style:preserve-3d;transition:transform .28s ease;touch-action:manipulation}
.card.flipped,.card.matched{transform:rotateY(180deg)}
.face{position:absolute;inset:0;border-radius:16px;display:grid;place-items:center;backface-visibility:hidden}
.front{background:linear-gradient(145deg,#183252,#0e2139);border:1px solid #2c4d70}
.front::after{content:"?";font-size:clamp(1.6rem,6vw,2.6rem);font-weight:700;color:var(--muted)}
.back{transform:rotateY(180deg);border:4px solid rgba(255,255,255,.2)}
.card.matched{opacity:.48;pointer-events:none}
.message{position:absolute;inset:0;display:grid;place-content:center;text-align:center;background:rgba(4,12,23,.84);padding:24px;border-radius:18px}
.message h1{margin:0 0 10px;font-size:clamp(2rem,7vw,4rem)}
.message p{color:var(--muted);max-width:440px;line-height:1.5;margin:0 auto 18px}
.primary,.secondary{border:0;border-radius:12px;padding:11px 18px;font-weight:700;cursor:pointer}
.primary{background:linear-gradient(135deg,#67e8f9,#8b5cf6);color:#05111e}
.secondary{background:#17314f;color:var(--text);border:1px solid var(--line)}
.footer{display:flex;justify-content:space-between;align-items:center;background:var(--panel);border:1px solid var(--line);border-radius:14px;padding:9px 12px}
@media(max-width:480px){
  .game-shell{padding:7px}
  .board{gap:7px}
  .card,.face{border-radius:12px}
  .stat{padding:6px}
  .stat strong{font-size:1.2rem}
}