* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Noto Sans JP', sans-serif;
  background: #fff;
  color: #222;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  padding: 20px;
}

.container {
  max-width: 500px;
  width: 100%;
  text-align: center;
}

.note {
  font-size: 0.9rem;
  color: #666;
  margin-bottom: 20px;
  padding: 8px 12px;
  background: #f5f5f5;
  border-radius: 6px;
  border-left: 3px solid #999;
}

.question-area {
  margin-bottom: 40px;
}

.question-text {
  font-size: 2rem;
  font-weight: 600;
  color: #222;
}

.weak {
  color: #e74c3c;
  font-size: 2.5rem;
}

.slider-container {
  margin: 40px 0;
}

#amountSlider {
  width: 100%;
  height: 8px;
  border-radius: 4px;
  background: #e0e0e0;
  outline: none;
  -webkit-appearance: none;
  margin-bottom: 20px;
}

#amountSlider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: #222;
  cursor: pointer;
  transition: transform 0.2s;
}

#amountSlider::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

#amountSlider::-moz-range-thumb {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: #222;
  cursor: pointer;
  border: none;
  transition: transform 0.2s;
}

#amountSlider::-moz-range-thumb:hover {
  transform: scale(1.2);
}

.amount-display {
  font-size: 2.5rem;
  font-weight: 700;
  color: #222;
}

#checkButton {
  background: #222;
  color: #fff;
  border: none;
  padding: 16px 48px;
  font-size: 1.1rem;
  border-radius: 8px;
  cursor: pointer;
  transition: transform 0.2s, opacity 0.2s;
  font-family: 'Noto Sans JP', sans-serif;
  font-weight: 600;
}

#checkButton:hover {
  transform: translateY(-2px);
}

#checkButton:active {
  transform: translateY(0);
}

.feedback {
  margin-top: 30px;
  padding: 20px;
  border-radius: 8px;
  font-size: 1.2rem;
  font-weight: 600;
  transition: opacity 0.3s;
}

.feedback.correct {
  background: #d4edda;
  color: #155724;
}

.feedback.incorrect {
  background: #f8d7da;
  color: #721c24;
}

.hidden {
  display: none;
}

.info-section {
  margin-top: 40px;
  text-align: left;
  padding: 30px;
  background: #f8f8f8;
  border-radius: 12px;
}

.info-section h3 {
  font-size: 1.5rem;
  margin-bottom: 15px;
  color: #222;
}

.info-section p {
  font-size: 1.1rem;
  line-height: 1.6;
  margin-bottom: 15px;
}

.info-section strong {
  color: #e74c3c;
}

.examples {
  margin-top: 20px;
}

.example {
  padding: 12px;
  background: #fff;
  margin-bottom: 10px;
  border-radius: 6px;
  border-left: 4px solid #222;
}

#tryAgain {
  margin-top: 20px;
  background: #fff;
  color: #222;
  border: 2px solid #222;
  padding: 12px 32px;
  font-size: 1rem;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s;
  font-family: 'Noto Sans JP', sans-serif;
  font-weight: 600;
  width: 100%;
}

#tryAgain:hover {
  background: #222;
  color: #fff;
}

.next-button.complete {
  background: #e74c3c;
  color: #fff;
  border-color: #e74c3c;
}

.next-button.complete:hover {
  background: #c0392b;
  border-color: #c0392b;
}

@media (max-width: 600px) {
  .question-text {
    font-size: 1.5rem;
  }

  .weak {
    font-size: 2rem;
  }

  .amount-display {
    font-size: 2rem;
  }

  .info-section {
    padding: 20px;
  }
}