:root{
  --bg:#04060b; --panel:#0a0f1a; --line:#152238;
  --cyan:#22d3ee; --mag:#e879f9; --grn:#4ade80; --gold:#fbbf24; --red:#fb7185;
  --txt:#dbe7f4; --dim:#5b7290;
}
*{box-sizing:border-box; -webkit-tap-highlight-color:transparent;}
html,body{height:100%;}
body{
  margin:0; background:var(--bg); color:var(--txt);
  font-family:'Rajdhani',sans-serif; overflow:hidden;
  display:flex; flex-direction:column; touch-action:none; user-select:none;
}
.gx-header{
  display:flex; align-items:center; justify-content:space-between;
  padding:10px 16px; border-bottom:1px solid var(--line);
  background:rgba(4,6,11,.9); z-index:20;
}
.gx-back{
  display:inline-flex; align-items:center; gap:6px;
  font-family:'Orbitron',sans-serif; font-size:11px; font-weight:700;
  letter-spacing:.14em; color:var(--cyan); text-decoration:none;
  padding:6px 12px; border:1px solid #164e63; border-radius:6px;
  background:rgba(34,211,238,.06); transition:.18s;
}
.gx-back:hover{background:rgba(34,211,238,.16); box-shadow:0 0 18px rgba(34,211,238,.35);}
.gx-brand{font-family:'Orbitron',sans-serif; font-weight:900; font-size:14px; letter-spacing:.18em; color:var(--txt); text-decoration:none;}
.gx-brand b{color:var(--cyan); font-weight:900;}
.gx-brand i{font-style:normal; color:var(--mag);}
main{flex:1; display:flex; flex-direction:column; align-items:center; justify-content:center; gap:12px; padding:10px; min-height:0;}
.hud{display:flex; align-items:center; gap:16px; flex-wrap:wrap; justify-content:center;}
.stat{display:flex; flex-direction:column; align-items:center; min-width:56px;}
.stat .k{font-size:10px; letter-spacing:.28em; color:var(--dim); font-weight:600;}
.stat .v{font-family:'Orbitron',sans-serif; font-size:18px; font-weight:700; color:var(--txt); line-height:1.15; text-shadow:0 0 12px rgba(74,222,128,.45);}
.stat.best .v{color:var(--gold); text-shadow:0 0 12px rgba(251,191,36,.5);}
.icon-btn{
  background:none; border:1px solid var(--line); color:var(--dim); border-radius:6px;
  width:36px; height:36px; cursor:pointer; font-size:15px; line-height:1; transition:.18s;
  display:flex; align-items:center; justify-content:center;
}
.icon-btn:hover:not(:disabled){color:var(--grn); border-color:var(--grn); box-shadow:0 0 14px rgba(74,222,128,.3);}
.icon-btn:disabled{opacity:.35; cursor:not-allowed;}
.icon-btn.wide2{width:auto; padding:0 12px; gap:5px; font-family:'Orbitron',sans-serif; font-size:11px; font-weight:700;}
.icon-btn.wide2 b{color:var(--grn);}
/* ===== board ===== */
.stage{position:relative; line-height:0;}
.board-wrap{position:relative; line-height:0;}
.board{
  position:relative; margin:0 auto;
  background:#0a101c; border:1px solid var(--line); border-radius:12px;
  box-shadow:0 0 60px rgba(74,222,128,.06), inset 0 0 60px rgba(0,0,0,.5);
}
.bg-cell{
  position:absolute; border-radius:8px;
  background:rgba(21,34,56,.55);
}
.tile{
  position:absolute; display:flex; align-items:center; justify-content:center;
  border-radius:8px; font-family:'Orbitron',sans-serif; font-weight:900;
  transition:transform .13s ease-out;
  will-change:transform;
}
.tile.new{animation:tNew .18s ease-out both;}
.tile.merged{animation:tMerge .22s cubic-bezier(.2,1.6,.4,1) both;}
@keyframes tNew{from{scale:.3; opacity:0}to{scale:1; opacity:1}}
@keyframes tMerge{0%{scale:1}45%{scale:1.22}100%{scale:1}}
/* floating score gain */
.gain{
  position:absolute; font-family:'Orbitron',sans-serif; font-weight:900; font-size:15px;
  pointer-events:none; z-index:5; animation:gainUp .8s ease-out both; text-shadow:0 0 12px currentColor;
}
@keyframes gainUp{from{opacity:1; translate:0 0}to{opacity:0; translate:0 -34px}}
/* toast */
.toast{
  position:absolute; top:12%; left:50%; transform:translateX(-50%); line-height:1.4;
  background:rgba(4,6,11,.92); border:1px solid var(--gold); border-radius:8px;
  padding:8px 18px; font-family:'Orbitron',sans-serif; font-size:11px; font-weight:700;
  letter-spacing:.2em; color:var(--gold); text-shadow:0 0 12px rgba(251,191,36,.7);
  box-shadow:0 0 30px rgba(251,191,36,.25); z-index:9; pointer-events:none; white-space:nowrap;
  animation:tIn .3s ease both;
}
.toast.out{animation:tOut .4s ease-in both;}
@keyframes tIn{from{opacity:0; transform:translateX(-50%) translateY(10px)}to{opacity:1; transform:translateX(-50%) translateY(0)}}
@keyframes tOut{from{opacity:1}to{opacity:0; transform:translateX(-50%) translateY(-10px)}}
/* ===== overlays ===== */
.overlay{
  position:absolute; inset:0; display:flex; align-items:center; justify-content:center;
  background:rgba(4,6,11,.86); backdrop-filter:blur(4px); border-radius:12px; z-index:10; overflow-y:auto;
}
.overlay.hidden{display:none;}
.panel{text-align:center; padding:22px; max-width:94%;}
.title{
  font-family:'Orbitron',sans-serif; font-weight:900; letter-spacing:.1em;
  font-size:clamp(26px,6vw,42px); margin:0 0 4px;
  color:var(--grn); text-shadow:0 0 24px rgba(74,222,128,.65), 0 0 60px rgba(74,222,128,.3);
}
.title .alt{color:var(--gold); text-shadow:0 0 24px rgba(251,191,36,.6);}
.subtitle{color:var(--dim); letter-spacing:.3em; font-size:11px; font-weight:600; margin-bottom:14px;}
.desc{color:var(--txt); font-size:15px; line-height:1.5; margin:0 0 16px; opacity:.9;}
.desc b{color:var(--grn);}
.sizes{display:flex; gap:10px; justify-content:center; margin:0 0 18px; flex-wrap:wrap;}
.size{
  cursor:pointer; border:1px solid var(--line); border-radius:10px; background:rgba(10,16,28,.7);
  color:var(--txt); padding:12px 18px; transition:.16s; font-family:'Rajdhani',sans-serif;
  display:flex; flex-direction:column; gap:2px; align-items:center;
}
.size b{font-family:'Orbitron',sans-serif; font-size:17px; letter-spacing:.08em;}
.size span{font-size:10px; letter-spacing:.24em; color:var(--dim); font-weight:600;}
.size:hover{border-color:var(--grn); box-shadow:0 0 18px rgba(74,222,128,.25);}
.size.sel{border-color:var(--grn); background:rgba(74,222,128,.1); box-shadow:0 0 22px rgba(74,222,128,.35);}
.size.sel b{color:var(--grn); text-shadow:0 0 12px rgba(74,222,128,.7);}
.btn{
  font-family:'Orbitron',sans-serif; font-size:13px; font-weight:700; letter-spacing:.2em;
  padding:12px 34px; cursor:pointer; border-radius:8px; border:1px solid var(--grn);
  background:rgba(74,222,128,.1); color:var(--grn); transition:.18s;
  text-shadow:0 0 10px rgba(74,222,128,.6); margin:4px;
}
.btn:hover{background:rgba(74,222,128,.22); box-shadow:0 0 30px rgba(74,222,128,.5); transform:translateY(-1px);}
.btn.ghost{border-color:var(--line); color:var(--dim); background:none; text-shadow:none; font-size:11px; padding:9px 20px;}
.btn.ghost:hover{color:var(--txt); border-color:var(--dim); box-shadow:none;}
.keys{color:var(--dim); font-size:13px; letter-spacing:.08em; margin-top:14px; line-height:1.9;}
.keys kbd{
  font-family:'Orbitron',sans-serif; font-size:10px; padding:2px 7px; margin:0 2px;
  border:1px solid var(--line); border-bottom-width:2px; border-radius:4px; color:var(--txt); background:#0a0f1a;
}
.final-score{font-family:'Orbitron',sans-serif; font-size:42px; font-weight:900; color:var(--txt); margin:6px 0 2px;}
.final-best{color:var(--gold); letter-spacing:.2em; font-size:12px; margin-bottom:10px; font-weight:600;}
.newbest{color:var(--gold); animation:pulse 1s infinite alternate; font-weight:700;}
@keyframes pulse{from{opacity:.6}to{opacity:1}}
.run-stats{display:flex; gap:16px; justify-content:center; color:var(--dim); font-size:13px; letter-spacing:.08em; margin-bottom:16px; flex-wrap:wrap;}
.run-stats b{color:var(--txt);}
/* ===== mobile arrows ===== */
.dpad{display:none; grid-template-columns:repeat(3,60px); grid-template-rows:repeat(2,52px); gap:8px;}
.dpad button{
  border:1px solid var(--line); background:rgba(74,222,128,.05); color:var(--grn);
  border-radius:10px; font-size:20px; cursor:pointer; touch-action:manipulation;
}
.dpad button:active{background:rgba(74,222,128,.25);}
.dpad .u{grid-column:2; grid-row:1;} .dpad .l{grid-column:1; grid-row:2;}
.dpad .d{grid-column:2; grid-row:2;} .dpad .r{grid-column:3; grid-row:2;}
@media (pointer:coarse){ .dpad{display:grid;} }
footer{padding:8px; text-align:center; color:var(--dim); font-size:11px; letter-spacing:.18em;}
footer a{color:var(--grn); text-decoration:none;}

/* ===== settings ===== */
.settings{margin-top:14px; text-align:left; border:1px solid var(--line); border-radius:10px; padding:8px 14px; background:rgba(10,15,26,.55);}
.setrow{display:flex; align-items:center; justify-content:space-between; gap:12px; padding:8px 2px; font-weight:600; letter-spacing:.08em; font-size:14px; color:#9fb0c8;}
.tog{font-family:'Orbitron',sans-serif; font-size:10px; font-weight:700; letter-spacing:.14em; padding:6px 14px; border-radius:999px; border:1px solid rgba(91,114,144,.5); background:transparent; color:var(--dim); cursor:pointer; transition:.15s; min-width:64px;}
.tog.on{border-color:#4ade80; color:#4ade80; box-shadow:0 0 12px rgba(74,222,128,.25);}