:root{color-scheme:dark;font-family:ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,sans-serif;line-height:1.5}*{box-sizing:border-box}html,body,#root{margin:0;min-height:100vh;background:#0a0a0a;color:#fafafa}.shell{min-height:100vh;display:grid;place-items:center;padding:2rem}.puzzle-container{display:flex;flex-direction:column;align-items:center;gap:1.5rem}.title{margin:0;font-size:2rem;font-weight:700;letter-spacing:-.03em;background:linear-gradient(135deg,#60a5fa,#a78bfa);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}.stats{display:flex;gap:2.5rem}.stat{display:flex;flex-direction:column;align-items:center;gap:.15rem}.stat-label{font-size:.7rem;text-transform:uppercase;letter-spacing:.15em;color:#ffffff73}.stat-value{font-size:1.6rem;font-weight:600;font-variant-numeric:tabular-nums;color:#fafafa}.board{display:grid;grid-template-columns:repeat(4,1fr);gap:6px;width:min(85vw,360px);height:min(85vw,360px)}.tile{display:flex;align-items:center;justify-content:center;border:none;border-radius:10px;font-size:1.5rem;font-weight:700;cursor:pointer;-webkit-user-select:none;user-select:none;background:linear-gradient(145deg,#1e293b,#0f172a);color:#e2e8f0;border:1px solid rgba(255,255,255,.08);transition:transform .1s ease,background .15s ease,box-shadow .15s ease;-webkit-tap-highlight-color:transparent}.tile:hover:not(:disabled){background:linear-gradient(145deg,#253449,#162032);border-color:#60a5fa40;box-shadow:0 0 12px #60a5fa1a;transform:scale(1.03)}.tile:active:not(:disabled){transform:scale(.97)}.tile-empty{background:transparent;border-color:#ffffff08;cursor:default}.tile-won{background:linear-gradient(145deg,#1e3a5f,#0c2340);border-color:#60a5fa4d;color:#93c5fd}.win-message{font-size:1.1rem;font-weight:600;color:#34d399;animation:popIn .3s ease}@keyframes popIn{0%{opacity:0;transform:scale(.8)}to{opacity:1;transform:scale(1)}}.shuffle-btn{padding:.65rem 2rem;font-size:.95rem;font-weight:600;border:none;border-radius:8px;cursor:pointer;background:linear-gradient(135deg,#3b82f6,#6366f1);color:#fff;letter-spacing:.01em;transition:transform .1s ease,box-shadow .15s ease,opacity .15s ease;-webkit-tap-highlight-color:transparent}.shuffle-btn:hover{box-shadow:0 4px 20px #6366f159;transform:translateY(-1px)}.shuffle-btn:active{transform:translateY(0)}