body {
  background: #d1d1d1;
  color: #000000;
  font-family: "Microsoft JhengHei", sans-serif;
  display: flex;
  flex-direction: column;
  align-items: center;
  margin: 0;
  padding: 20px;
}

header h1 {
  margin: 0 0 10px 0;
}

#controls {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  margin-bottom: 20px;
}

#numbers {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: center;
  font-size: 1.2rem;
}

.number {
  padding: 6px 12px;
  background: #222;
  border-radius: 6px;
  min-width: 24px;
  text-align: center;
  transition: all 0.2s;
}

.number.active {
  background: #ffd166;
  color: #111;
}

.number.compare {
  background: #ff6b6b;
  color: #fff;
}

.number.sorted {
  background: #9be7a3;
  color: #111;
}

button.primary {
  background: #00d1b2;
  color: #042825;
}