body {
  font-family: 'ヒラギノ角ゴシック', 'Hiragino Kaku Gothic Pro', Meiryo, sans-serif;
  background: linear-gradient(to bottom, #a7e8af, #f0fff5);
  color: #333;
  text-align: center;
  margin: 0;
  padding: 0;
}

.container {
  max-width: 750px;
  margin: 20px auto;
  padding: 25px;
  background-color: #fff9f0;
  border-radius: 20px;
  box-shadow: 0 8px 20px rgba(0,0,0,0.15);
  border: 3px solid #c0f0c0;
}

h1 {
  color: #2e8b57;
  font-size: 32px;
  margin-bottom: 15px;
}

.controls {
  margin-bottom: 15px;
}

.controls button, .controls select {
  margin: 5px;
  padding: 10px 15px;
  border-radius: 12px;
  border: 2px solid #2e8b57;
  background-color: #d4f0d4;
  cursor: pointer;
  font-size: 14px;
  transition: 0.2s;
}

.controls button:hover, .controls select:hover {
  background-color: #a0e0a0;
}

#status {
  margin-bottom: 15px;
  font-weight: bold;
  font-size: 16px;
}

.question {
  font-size: 20px;
  margin-bottom: 15px;
  background-color: #e0ffe0;
  padding: 15px;
  border-radius: 15px;
  border: 2px dashed #2e8b57;
}

.choices {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-bottom: 15px;
}

.choices button {
  padding: 12px 22px;
  border-radius: 15px;
  border: 2px solid #3cb371;
  background-color: #f0fff0;
  cursor: pointer;
  font-size: 16px;
  transition: 0.2s;
}

.choices button.correct {
  background-color: #98fb98;
  border-color: #006400;
  transform: scale(1.05);
}

.choices button.wrong {
  background-color: #ffb6b6;
  border-color: #8b0000;
  transform: scale(0.98);
}

.choices button:hover {
  background-color: #b0ffc0;
}

.result {
  font-size: 18px;
  margin-bottom: 15px;
  min-height: 24px;
  font-weight: bold;
  color: #333;
}

.turtle {
  width: 140px;
  height: auto;
  display: none;
  margin: 15px auto;
  transition: transform 0.3s;
}

.turtle.show {
  transform: scale(1.2);
}

ul#historyList {
  list-style-type: none;
  padding-left: 0;
  text-align: left;
  max-height: 180px;
  overflow-y: auto;
  border-top: 2px dotted #2e8b57;
  margin-top: 10px;
  padding-top: 5px;
  background-color: #f0fff0;
  border-radius: 10px;
}

canvas#scoreChart {
  margin-top: 15px;
  background-color: #f0fff0;
  border-radius: 12px;
  padding: 10px;
  border: 2px solid #2e8b57;
}