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

body {
  font-family: 'Space Mono', monospace;
  background: white;
  color: black;
  padding: 20px;
}

.container {
  max-width: 800px;
  margin: 0 auto;
}

#timer {
  font-size: 18px;
  font-weight: bold;
  margin-bottom: 10px;
  text-align: center;
  color: #555;
}

#score {
  font-size: 18px;
  font-weight: bold;
  margin-bottom: 15px;
  text-align: center;
}

#showAnswer {
  display: block;
  margin: 0 auto 20px;
  padding: 10px 24px;
  font-family: 'Space Mono', monospace;
  font-size: 14px;
  background: black;
  color: white;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.15s;
}

#showAnswer:hover {
  background: #333;
}

#showAnswer:active {
  transform: scale(0.95);
}

#primes {
  display: grid;
  grid-template-columns: repeat(10, 1fr);
  gap: 12px;
}

.number {
  padding: 8px 16px;
  border: 1px solid black;
  border-radius: 4px;
  font-size: 16px;
  transition: all 0.15s;
  cursor: pointer;
  user-select: none;
}

.number:hover {
  transform: scale(1.05);
  background: #f0f0f0;
}

.number.correct {
  background: #90EE90;
  border-color: #228B22;
  cursor: default;
}

.number.wrong {
  background: #FFB6C6;
  border-color: #DC143C;
  cursor: default;
}

.number.correct:hover,
.number.wrong:hover {
  transform: none;
  background: #90EE90;
}

.number.wrong:hover {
  background: #FFB6C6;
}

@media (max-width: 600px) {
  #primes {
    grid-template-columns: repeat(10, 1fr);
    gap: 8px;
  }
  
  #score {
    font-size: 16px;
    margin-bottom: 15px;
  }
  
  .number {
    padding: 6px 12px;
    font-size: 14px;
  }
}