* { box-sizing: border-box; }
body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: #f6f7fb;
  margin: 0;
  padding: 16px;
  color: #1f2330;
}
.wrap {
  max-width: 480px;
  margin: 0 auto;
  text-align: center;
}
.status {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
  font-variant-numeric: tabular-nums;
  font-size: 18px;
}
#newbtn {
  background: #4f46e5;
  color: white;
  border: 0;
  padding: 8px 14px;
  border-radius: 6px;
  cursor: pointer;
}
#newbtn:hover { background: #4338ca; }
.board {
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  gap: 0;
  border: 2px solid #1f2330;
  border-radius: 4px;
  overflow: hidden;
  background: white;
  user-select: none;
}
.cell {
  aspect-ratio: 1 / 1;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  font-weight: 500;
  border: 1px solid #d0d4de;
  background: white;
  cursor: pointer;
  transition: background 0.1s;
}
.cell:nth-child(3n):not(:nth-child(9n)) { border-right: 2px solid #1f2330; }
.cell:nth-child(n+19):nth-child(-n+27),
.cell:nth-child(n+46):nth-child(-n+54) { border-bottom: 2px solid #1f2330; }
.cell.given { background: #eef0f6; color: #1f2330; cursor: default; }
.cell.selected { background: #c7d2fe !important; }
.cell.invalid { color: #dc2626; }
.cell.user { color: #4f46e5; }
.result {
  margin-top: 16px;
  padding: 12px;
  background: #d1fae5;
  color: #065f46;
  border-radius: 6px;
  font-size: 18px;
  font-weight: 600;
}
.result.hidden { display: none; }
.keypad {
  margin-top: 12px;
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 6px;
}
.keypad button {
  padding: 12px 0;
  font-size: 18px;
  background: white;
  border: 1px solid #d0d4de;
  border-radius: 6px;
  cursor: pointer;
}
.keypad button:hover { background: #eef0f6; }