:root{--bg:#f6f1ea;--paper:#fffdf9;--ink:#2b2420;--muted:#7a6c62;--line:#e4d9cc;--accent:#c4552f;--board:#cdbfae;--cell:#ddd1c3}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.55 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif}
a{color:var(--accent)}
header{max-width:960px;margin:0 auto;padding:18px 20px;display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap}
.logo{font-weight:800;font-size:1.25rem;text-decoration:none;color:var(--ink);letter-spacing:-.01em}
.logo b{color:var(--accent)}
nav a{color:var(--muted);text-decoration:none;margin-left:18px;font-size:.95rem}
nav a:hover,nav a.on{color:var(--ink)}
nav a:first-child{margin-left:0}
main{max-width:960px;margin:0 auto;padding:8px 20px 40px}
.game-wrap{display:grid;grid-template-columns:minmax(0,440px) 1fr;gap:40px;align-items:start}
@media(max-width:820px){.game-wrap{grid-template-columns:1fr;gap:24px}}
h1{font-size:2.2rem;line-height:1.15;margin:.3em 0 .4em;letter-spacing:-.02em}
h2{font-size:1.3rem;margin:1.6em 0 .5em}
.lead{color:var(--muted);margin:0 0 1em}
.bar{display:flex;gap:10px;align-items:stretch;margin-bottom:14px}
.score{background:var(--board);color:#fff;border-radius:10px;padding:6px 14px;text-align:center;min-width:86px}
.score small{display:block;font-size:.72rem;text-transform:uppercase;letter-spacing:.06em;opacity:.85}
.score span{font-size:1.25rem;font-weight:800}
.btn{margin-left:auto;background:var(--accent);color:#fff;border:0;border-radius:10px;padding:0 18px;font:inherit;font-weight:700;cursor:pointer}
.btn:hover{filter:brightness(1.07)}
.board{position:relative;background:var(--board);border-radius:14px;padding:10px;display:grid;grid-template-columns:repeat(4,1fr);gap:10px;aspect-ratio:1;touch-action:none;user-select:none;-webkit-user-select:none}
.cell{background:var(--cell);border-radius:8px;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:clamp(1.2rem,6.5vw,2.2rem);color:#5b4d43;transition:background .12s}
.cell.pop{animation:pop .14s ease-out}
@keyframes pop{0%{transform:scale(.85)}100%{transform:scale(1)}}
.v2{background:#efe5d8}.v4{background:#ecdcc4}.v8{background:#f0b07b;color:#fff}.v16{background:#ee9560;color:#fff}.v32{background:#e97a52;color:#fff}.v64{background:#e05b34;color:#fff}
.v128{background:#e8c86a;color:#fff;font-size:clamp(1rem,5.5vw,1.9rem)}.v256{background:#e6c157;color:#fff;font-size:clamp(1rem,5.5vw,1.9rem)}.v512{background:#e3b944;color:#fff;font-size:clamp(1rem,5.5vw,1.9rem)}
.v1024{background:#7fa36b;color:#fff;font-size:clamp(.9rem,4.5vw,1.5rem)}.v2048{background:#4f8a5b;color:#fff;font-size:clamp(.9rem,4.5vw,1.5rem)}.big{background:#3b4a63;color:#fff;font-size:clamp(.8rem,4vw,1.3rem)}
.overlay{position:absolute;inset:0;border-radius:14px;background:rgba(246,241,234,.86);display:none;flex-direction:column;align-items:center;justify-content:center;gap:12px;text-align:center;padding:20px}
.overlay.show{display:flex}
.overlay p{font-size:1.6rem;font-weight:800;margin:0}
.hint{color:var(--muted);font-size:.9rem;margin-top:12px}
.side .card{background:var(--paper);border:1px solid var(--line);border-radius:14px;padding:18px 20px;margin-bottom:16px}
.side .card h3{margin:0 0 .4em;font-size:1.05rem}
.side ol,.side ul{margin:.3em 0 0;padding-left:1.2em}
.records li{display:flex;justify-content:space-between;gap:12px;padding:3px 0;border-bottom:1px dashed var(--line)}
.records li:last-child{border:0}
.muted{color:var(--muted)}
.text{max-width:680px}
.text p,.text li{margin:.6em 0}
footer{max-width:960px;margin:0 auto;padding:24px 20px 40px;color:var(--muted);font-size:.88rem;border-top:1px solid var(--line)}
footer a{color:var(--muted)}