:root{
  --bg:#faf8ef;
  --board:#bbada0;
  --tile-empty:#cdc1b4;
  --text:#776e65;
  --text-light:#f9f6f2;
  --accent:#8f7a66;
  --btn:#8f7a66;
  --btn-hover:#7a6656;
  --safe-top: env(safe-area-inset-top);
  --safe-bottom: env(safe-area-inset-bottom);
}
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;display:flex;align-items:center;justify-content:center;
  background:var(--bg);color:var(--text);font-family:Inter,system-ui,Segoe UI,Roboto,Helvetica,Arial,sans-serif;
  overscroll-behavior:none;
  padding-bottom:calc(12px + var(--safe-bottom));
  padding-top:var(--safe-top);
  touch-action:manipulation;
}
.wrap{width:min(95vw,560px);}
header{display:flex;justify-content:space-between;align-items:center;margin-bottom:14px}
h1{font-size:42px;margin:0;color:var(--accent);letter-spacing:1px}
.scores{display:flex;gap:10px}
.badge{background:#bbada0;color:#fff;border-radius:10px;padding:8px 12px;min-width:90px;text-align:center}
.badge .label{font-size:11px;opacity:.9}
.badge .value{font-weight:800;font-size:18px}
.controls{display:flex;gap:8px;margin:10px 0 8px;flex-wrap:wrap;align-items:center}
.controls .right{margin-left:auto;display:flex;gap:8px;align-items:center}
button{cursor:pointer;border:none;border-radius:10px;padding:10px 14px;background:var(--btn);color:white;font-weight:600}
button:hover{background:var(--btn-hover)}
.board{position:relative;background:var(--board);border-radius:14px;padding:10px;display:grid;grid-template-columns:repeat(4,1fr);grid-gap:10px;aspect-ratio:1/1;
  touch-action:none;
}
.cell{background:var(--tile-empty);border-radius:10px}
.tile{position:absolute;inset:auto;display:flex;align-items:center;justify-content:center;border-radius:10px;font-weight:800;font-size:28px;color:var(--text-light);
  width:calc((100% - 50px)/4);height:calc((100% - 50px)/4);
  /* aumentado tiempo y easing para movimiento más agradable */
  transition:transform .20s cubic-bezier(.22,.9,.32,1), left .12s ease-in, top .12s ease-in, opacity .16s ease-in;}
.tile.new{animation:pop .12s ease-out}
@keyframes pop{0%{transform:scale(.5)}100%{transform:scale(1)}}

/* Colors per value */
.v2{background:#eee4da;color:#776e65}
.v4{background:#ede0c8;color:#776e65}
.v8{background:#f2b179}
.v16{background:#f59563}
.v32{background:#f67c5f}
.v64{background:#f65e3b}
.v128{background:#edcf72;font-size:24px}
.v256{background:#edcc61;font-size:24px}
.v512{background:#edc850;font-size:24px}
.v1024{background:#edc53f;font-size:20px}
.v2048{background:#edc22e;font-size:20px}
.v4096{background:#3c3a32}

.msg{margin-top:12px;min-height:24px}
.toast{background:#000000aa;color:#fff;position:fixed;left:50%;bottom:20px;transform:translateX(-50%);padding:10px 14px;border-radius:10px;font-size:14px;opacity:0;pointer-events:none;transition:opacity .2s}
.toast.show{opacity:1}

@media (max-width:380px){
  h1{font-size:34px}
  .badge{min-width:72px}
  .tile{font-size:22px}
  .v1024,.v2048{font-size:18px}
}
label.toggle{display:inline-flex;gap:6px;align-items:center;font-size:13px}
label.toggle input{width:18px;height:18px}

/* fade while moving */
.board.fading .tile{opacity:0.45}

/* slide-in directions (start state). --cell será establecido desde JS según tamaño real */
.tile.slide-in-left{ transform: translateX(calc(-1 * var(--cell, 86px))) scale(1); }
.tile.slide-in-right{ transform: translateX(calc(var(--cell, 86px))) scale(1); }
.tile.slide-in-up{ transform: translateY(calc(-1 * var(--cell, 86px))) scale(1); }
.tile.slide-in-down{ transform: translateY(calc(var(--cell, 86px))) scale(1); }

/* make sure new-pop animation still visible */
.tile.new{animation:pop .12s ease-out}