:root{
  --bg:#0a101c; --card:#121a2b; --card2:#182338; --ink:#e9eefb; --ink2:#93a3c0;
  --line:#22304a; --accent:#22d3ee; --accent2:#f59e0b; --good:#34d399; --r:16px;
}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);font-family:system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif;
  font-size:16.5px;line-height:1.65;-webkit-text-size-adjust:100%}
a{color:var(--accent);text-decoration:none}a:hover{text-decoration:underline}
.wrap{max-width:680px;margin:0 auto;padding:0 16px}
.head{border-bottom:1px solid var(--line);position:sticky;top:0;background:rgba(10,16,28,.95);
  backdrop-filter:blur(6px);z-index:20}
.head .wrap{display:flex;align-items:center;justify-content:space-between;height:56px}
.brand{font-weight:800;font-size:19px;color:var(--ink);letter-spacing:-.02em}
.brand span{color:var(--accent)}
.hero{padding:22px 0 6px}
.hero h1{font-size:clamp(24px,5.5vw,32px);line-height:1.2;margin:0 0 8px;letter-spacing:-.02em}
.hero p{margin:0;color:var(--ink2);font-size:16px}

/* hub cards */
.grid2{display:grid;gap:12px;margin:18px 0}
@media(min-width:520px){.grid2{grid-template-columns:1fr 1fr}}
.gcard{display:block;background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:16px}
.gcard:hover{text-decoration:none;border-color:var(--accent);transform:translateY(-1px)}
.gcard .ico{font-size:26px}
.gcard b{display:block;margin:6px 0 4px;font-size:17px;color:var(--ink)}
.gcard span{font-size:14px;color:var(--ink2)}

/* game shell */
.shell{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:14px;margin:16px 0}
.bar{display:flex;justify-content:space-between;align-items:center;gap:10px;margin-bottom:12px;flex-wrap:wrap}
.stat{font-size:13.5px;color:var(--ink2)}
.stat b{color:var(--ink);font-size:16px;margin-left:4px}
.btn{background:var(--card2);border:1px solid var(--line);color:var(--ink);border-radius:10px;
  padding:9px 14px;font-size:14.5px;font-weight:700;cursor:pointer;font-family:inherit}
.btn:hover{border-color:var(--accent)}
.msg{min-height:22px;font-size:14.5px;color:var(--accent2);text-align:center;margin-top:10px}

/* 2048 */
#g-board{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;aspect-ratio:1/1;
  background:var(--card2);padding:8px;border-radius:12px;touch-action:none}
.cell{display:grid;place-items:center;border-radius:8px;background:#1b2740;font-weight:800;
  font-size:clamp(18px,5vw,26px);color:#cfe0ff}
.cell.v2{background:#1f3a5f;color:#dbeafe}
.cell.v4{background:#1e4976;color:#dbeafe}
.cell.v8{background:#0e7490;color:#ecfeff}
.cell.v16{background:#0d9488;color:#ecfdf5}
.cell.v32{background:#16a34a;color:#f0fdf4}
.cell.v64{background:#65a30d;color:#f7fee7}
.cell.v128{background:#ca8a04;color:#fefce8}
.cell.v256{background:#d97706;color:#fffbeb}
.cell.v512{background:#ea580c;color:#fff7ed}
.cell.v1024{background:#dc2626;color:#fef2f2}
.cell.v2048{background:#be123c;color:#fff1f2}
.cell.vbig{background:#7c3aed;color:#f5f3ff}

/* snake */
#g-canvas{width:100%;max-width:360px;margin:0 auto;display:block;border-radius:12px;background:#0b1220;
  border:1px solid var(--line);touch-action:none}
.dpad{display:grid;grid-template-columns:repeat(3,64px);gap:8px;justify-content:center;margin-top:12px}
.dpad button{height:52px;border-radius:12px;background:var(--card2);border:1px solid var(--line);
  color:var(--ink);font-size:18px;cursor:pointer;font-family:inherit}
.dpad .sp{visibility:hidden}

/* memory + ttt grids */
#g-grid{display:grid;gap:8px;justify-content:center}
#g-grid{grid-template-columns:repeat(4,minmax(0,1fr))}
.mcard{aspect-ratio:1/1;font-size:clamp(22px,7vw,32px);border-radius:12px;background:var(--card2);
  border:1px solid var(--line);color:transparent;cursor:pointer;display:grid;place-items:center}
.mcard.open,.mcard.done{background:#0e7490;color:#fff;border-color:var(--accent)}
.mcard.done{opacity:.55}
#g-grid.ttt{grid-template-columns:repeat(3,76px)}
.tcell{width:76px;height:76px;font-size:30px;font-weight:800;border-radius:12px;background:var(--card2);
  border:1px solid var(--line);color:var(--accent);cursor:pointer;font-family:inherit}
.tcell:hover{border-color:var(--accent)}

/* reaction */
.pad{height:220px;border-radius:16px;background:var(--card2);border:1px solid var(--line);
  display:grid;place-items:center;font-size:19px;font-weight:800;color:var(--ink2);cursor:pointer;
  text-align:center;padding:16px;user-select:none}
.pad.wait{background:#3f2d0b;color:#fbbf24}
.pad.go{background:#065f46;color:#6ee7b7;border-color:#10b981}

/* math */
#g-q{font-size:clamp(26px,7vw,34px);font-weight:800;text-align:center;margin:8px 0 14px;letter-spacing:.02em}
#g-input{width:100%;padding:14px;border-radius:12px;border:1px solid var(--line);background:var(--card2);
  color:var(--ink);font-size:20px;text-align:center;font-family:inherit}
#g-input:focus{outline:2px solid var(--accent);border-color:var(--accent)}

/* ad slots */
.ad-slot{margin:22px 0;min-height:100px;border:1px dashed var(--line);border-radius:14px;background:var(--card);
  display:flex;align-items:center;justify-content:center;color:var(--ink2);font-size:11px;
  letter-spacing:.08em;text-transform:uppercase}
.ad-slot.tall{min-height:250px}

/* content + footer */
h2{font-size:20px;margin:28px 0 8px}
h3{font-size:17px;margin:18px 0 6px}
p,li{color:#c3cfe6}
ul{padding-left:22px}li{margin:6px 0}
.next{display:block;background:var(--card);border:1px solid var(--line);border-radius:14px;padding:16px;margin:20px 0}
.next .lbl{font-size:12px;text-transform:uppercase;letter-spacing:.07em;color:var(--accent);font-weight:700}
.next b{display:block;font-size:18px;margin-top:4px;color:var(--ink)}
.next span{font-size:14px;color:var(--ink2)}
.foot{border-top:1px solid var(--line);margin-top:32px;padding:22px 0 40px;font-size:13px;color:var(--ink2)}
.foot .cols{display:flex;flex-wrap:wrap;gap:10px 16px;margin-bottom:14px}