:root{
  --bg:#1A1A2E;
  --bg-2:#262646;
  --board:#2E2E52;
  --slot:#3A3A63;
  --ink:#F3F0FF;
  --muted:#A3A0C9;
  --gold:#EDC22E;
  --paper:#FFFFFF;
  --paper-ink:#1A1A2E;
  --paper-muted:#60608A;
  --font:"Rubik", "Segoe UI", system-ui, sans-serif;
  color-scheme:dark;
}
*{box-sizing:border-box}
html,body{background:var(--bg)}
body{margin:0;color:var(--ink);font:16px/1.3 var(--font);padding-inline:10px;padding-block:8px 10px;-webkit-tap-highlight-color:transparent;overscroll-behavior:none;touch-action:manipulation}
.app{max-width:520px;margin-inline:auto;width:100%;min-height:calc(100dvh - 18px);display:grid;grid-template-rows:auto auto 1fr auto;grid-template-columns:minmax(0,1fr);gap:8px}

.bar{display:flex;align-items:center;justify-content:space-between;gap:10px;min-height:44px}
.back{color:var(--muted);text-decoration:none;font-weight:600;font-size:15px;white-space:nowrap}
.back:hover{color:var(--ink)}
.title{margin:0;font-weight:800;font-size:clamp(1.3rem,4vw,1.9rem);white-space:nowrap;letter-spacing:.02em}
.title span{color:var(--gold)}
.bar-actions{display:flex;gap:8px;align-items:center}
.icon-btn{width:42px;height:42px;border-radius:12px;border:0;background:var(--bg-2);color:var(--ink);display:grid;place-items:center;cursor:pointer;padding:0}
.icon-btn span{display:grid;place-items:center}
.icon-btn span[hidden]{display:none}
.icon-btn svg{width:22px;height:22px}
button{font:inherit;cursor:pointer}
.btn{border:0;border-radius:12px;background:var(--bg-2);color:var(--ink);font-weight:700;padding:10px 18px;box-shadow:0 4px 0 rgba(0,0,0,.4)}
.btn:active{translate:0 3px;box-shadow:0 1px 0 rgba(0,0,0,.4)}
.btn.small{padding:8px 14px;font-size:15px}
.btn.primary{background:var(--gold);color:#4A3600;box-shadow:0 4px 0 #B3920F}
.btn.light{background:#E2E0F0;color:var(--paper-ink);box-shadow:0 4px 0 #B9B6D2}
:focus-visible{outline:3px solid var(--gold);outline-offset:2px}

.hud{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:6px}
.hud .cell{background:var(--bg-2);border-radius:10px;padding:4px 10px;display:grid;line-height:1.15;min-width:0}
.hud .cell span{font-size:10.5px;font-weight:600;letter-spacing:.09em;text-transform:uppercase;color:var(--muted)}
.hud .cell b{font-size:1.15rem;font-weight:700;font-variant-numeric:tabular-nums;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.hud .cell b.up{animation:bump .4s}
@keyframes bump{40%{scale:1.18;color:var(--gold)}}

.board-wrap{display:grid;place-items:center;min-height:0;min-width:0}
.board{position:relative;width:min(100%,min(66vh,440px));aspect-ratio:1;background:var(--board);border-radius:16px;padding:var(--gap);touch-action:none;--gap:10px}
.grid,.tiles{position:absolute;inset:var(--gap)}
.grid{display:grid;gap:var(--gap)}
.grid i{background:var(--slot);border-radius:10px}
.tiles{pointer-events:none}
.tile{position:absolute;width:var(--sz);height:var(--sz);border-radius:10px;display:grid;place-items:center;
  font-weight:800;font-variant-numeric:tabular-nums;color:#2B2B40;background:#EEE4DA;
  translate:calc(var(--x) * (var(--sz) + var(--gap))) calc(var(--y) * (var(--sz) + var(--gap)));
  transition:translate .13s ease-out;will-change:translate}
.tile.new{animation:appear .18s ease-out}
.tile.merged{animation:pop .2s ease-out}
@keyframes appear{from{scale:.1;opacity:0}}
@keyframes pop{40%{scale:1.16}}
.v2{background:#EEE4DA} .v4{background:#EDE0C8}
.v8{background:#F2B179;color:#FFF8F0} .v16{background:#F59563;color:#FFF8F0}
.v32{background:#F67C5F;color:#FFF8F0} .v64{background:#F65E3B;color:#FFF8F0}
.v128{background:#EDCF72;color:#FFF8F0} .v256{background:#EDCC61;color:#FFF8F0}
.v512{background:#EDC850;color:#FFF8F0} .v1024{background:#EDC53F;color:#FFF8F0}
.v2048{background:#EDC22E;color:#FFF8F0;box-shadow:0 0 20px rgba(237,194,46,.75)}
.vbig{background:#3C3A32;color:#FFF8F0;box-shadow:0 0 20px rgba(255,255,255,.3)}

.tools{display:grid;grid-template-columns:1fr 1fr;gap:6px}
.tool{border:0;border-radius:12px;background:var(--bg-2);color:var(--ink);font-weight:700;font-size:14px;padding:9px 0;display:grid;justify-items:center;gap:1px;box-shadow:0 3px 0 rgba(0,0,0,.45)}
.tool span{font-size:1.2rem;line-height:1}
.tool:active{translate:0 2px;box-shadow:0 1px 0 rgba(0,0,0,.45)}
.tool:disabled{opacity:.4;box-shadow:none;cursor:default}
.hintline{grid-column:1 / -1;margin:0;text-align:center;color:var(--muted);font-size:12.5px;font-weight:500;min-height:1.2em}

.overlay{position:fixed;inset:0;z-index:20;display:grid;place-items:center;padding:16px;background:rgba(10,10,20,.86);overflow-y:auto}
.overlay[hidden]{display:none}
.sheet{width:100%;max-width:430px;background:var(--paper);color:var(--paper-ink);border-radius:20px;padding:20px 22px;display:grid;gap:14px;box-shadow:0 20px 50px rgba(0,0,0,.5)}
.sheet.center{text-align:center;justify-items:center;max-width:380px}
h2{margin:0;text-align:center;font-weight:800;font-size:2rem}
h2 span{color:#B3920F}
.help{margin:0;font-size:13.5px;color:var(--paper-muted);line-height:1.55}
.help b{color:var(--paper-ink)}
.help.small{font-size:12.5px;text-align:center}
.lbl{margin:2px 0 0;font-size:12px;font-weight:800;letter-spacing:.09em;text-transform:uppercase;color:var(--paper-muted)}
.levels{display:grid;gap:8px}
.levels button{border:0;border-radius:12px;padding:11px 16px;background:#EFEDF7;color:var(--paper-ink);font-weight:700;display:flex;justify-content:space-between;align-items:center;gap:10px;box-shadow:0 3px 0 #CBC8DE}
.levels button:active{translate:0 2px;box-shadow:0 1px 0 #CBC8DE}
.levels button b{font-size:1.05rem}
.levels button small{color:var(--paper-muted);font-weight:600;font-variant-numeric:tabular-nums}
.trophy{font-size:56px;line-height:1}
.end-title{margin:0;font-weight:800;font-size:1.6rem;text-wrap:balance}
.results{display:grid;grid-template-columns:1fr 1fr;gap:10px;width:100%}
.results div{background:#F1EFF8;border-radius:12px;padding:8px;display:grid}
.results span{font-size:10.5px;font-weight:700;letter-spacing:.09em;text-transform:uppercase;color:var(--paper-muted)}
.results b{font-size:1.7rem;font-variant-numeric:tabular-nums}
.lead{margin:0;color:var(--paper-muted);font-weight:600}
.row{display:flex;gap:10px;flex-wrap:wrap;justify-content:center}

@media (max-width:640px){
  .back-tx{display:none}
  .back{font-size:20px}
}
@media (prefers-reduced-motion:reduce){
  .tile{transition:none}
  .tile.new,.tile.merged,.hud .cell b.up{animation:none}
}