.nim-piles { display: flex; flex-direction: column; gap: 12px; align-items: center; }
.nim-pile {
  display: flex; flex-wrap: wrap; gap: 6px; justify-content: center;
  padding: 10px 14px; border-radius: 12px; cursor: pointer;
  background: #f1f5f9; border: 2px solid transparent; max-width: 92vw;
  transition: border .12s, background .12s;
}
.nim-pile.sel { border-color: #2563eb; background: #e0ecff; }
.nim-tok { width: 18px; height: 18px; border-radius: 50%; background: #f59e0b; box-shadow: inset 0 -2px 0 rgba(0,0,0,.2); }
.nim-control { display: flex; flex-direction: column; align-items: center; }