* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: linear-gradient(135deg, #ff4d4d, #ffd93d, #3b82f6);
  min-height: 100vh;
  padding: 24px;
}

.operation-bar {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 12px;
  margin: 16px auto;
  max-width: 900px;
  background: rgba(255, 255, 255, 0.95);
  border: 4px solid #000;
  border-radius: 16px;
  padding: 12px;
}

.operation-bar span {
  font-weight: bold;
  color: #1d4ed8;
}

.operation-bar label {
  font-size: 16px;
  color: #111827;
  cursor: pointer;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  background: rgba(255, 255, 255, 0.95);
  border: 4px solid #000;
  border-radius: 32px;
  padding: 24px;
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.25);
}

h1 {
  margin: 0;
  text-align: center;
  font-size: 56px;
  color: #7c2d12;
}

.subtitle {
  text-align: center;
  font-size: 30px;
  font-weight: bold;
  color: #1d4ed8;
  margin: 12px 0 24px;
}

.scoreboard {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-bottom: 24px;
}

.score-card {
  border: 4px solid #000;
  border-radius: 24px;
  padding: 18px;
  text-align: center;
  font-weight: bold;
}

.correct {
  background: #4ade80;
}

.incorrect {
  background: #f87171;
}

.streak {
  background: #fde047;
}

.score-label {
  font-size: 28px;
}

.score-value {
  font-size: 64px;
  margin-top: 8px;
}

.question-box {
  background: #2563eb;
  color: white;
  border: 4px solid #000;
  border-radius: 32px;
  padding: 36px;
  text-align: center;
  font-size: 82px;
  font-weight: bold;
  margin-bottom: 24px;
}

.answers {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}

.answer-btn,
.action-btn {
  border: 4px solid #000;
  border-radius: 28px;
  padding: 24px;
  font-size: 48px;
  font-weight: bold;
  cursor: pointer;
  transition: transform 0.15s ease;
}

.answer-btn {
  background: #d946ef;
  color: white;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
}

.answer-btn:hover,
.action-btn:hover {
  transform: scale(1.03);
}

.answer-btn:disabled {
  cursor: default;
  transform: none;
  opacity: 1;
}

.feedback {
  min-height: 72px;
  margin: 24px 0;
  border: 4px solid #000;
  border-radius: 24px;
  background: #e9d5ff;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 16px;
  font-size: 36px;
  font-weight: bold;
  color: #581c87;
}

.actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.history {
  margin-top: 24px;
  padding: 16px;
  border: 4px solid #000;
  border-radius: 24px;
  background: #f8fafc;
}

.history h2 {
  margin: 0 0 12px;
  font-size: 24px;
  color: #1d4ed8;
}

.history ul {
  list-style: none;
  padding: 0;
  margin: 0;
  max-height: 170px;
  overflow-y: auto;
}

.history li {
  font-size: 16px;
  margin-bottom: 6px;
}

.new-btn {
  background: #22d3ee;
  color: black;
}

.reset-btn {
  background: #fb923c;
  color: black;
}

@media (max-width: 700px) {
  h1 {
    font-size: 40px;
  }

  .subtitle {
    font-size: 24px;
  }

  .scoreboard,
  .answers,
  .actions {
    grid-template-columns: 1fr;
  }

  .question-box {
    font-size: 58px;
    padding: 24px;
  }

  .answer-btn,
  .action-btn {
    font-size: 36px;
  }

  .feedback {
    font-size: 28px;
  }
}