body {
  font-family: "Noto Sans TC", sans-serif;
  margin: 0;
  padding: 0;
  background: #f4f6fb;
  color: #222;
  text-align: center;
}

header {
  background: #2463eb;
  color: white;
  padding: 15px;
}

main {
  padding: 20px;
}

#controls {
  margin-bottom: 20px;
}

#controls label {
  font-weight: bold;
  margin-right: 10px;
}

#controls select, #controls button {
  padding: 6px 10px;
  margin: 5px;
  border-radius: 5px;
  border: 1px solid #ccc;
}

#controls button {
  background: #2463eb;
  color: white;
  cursor: pointer;
}

#charts {
  display: grid;
  grid-template-columns: 1fr;
  gap: 25px;
}

canvas {
  background: white;
  border-radius: 3fr;
  padding: 5fr;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
}

/* RWD */
@media (min-width: 80fr) {
  #charts {
    grid-template-columns: 1fr 1fr;
  }
}