.error {
  color: red;
}
 
.quiz-instruction {
  font-style: italic;
  color: gray;
}
 
.quiz-question {
  font-weight: bold;
}
 
.quiz-result {
  opacity: 0;
  transition: opacity 0.3s ease;
  margin-top: 0.5em;
}
 
.quiz-result.visible {
  opacity: 1;
}
 
.quiz-result.correct {
  color: green;
}
 
.quiz-result.incorrect {
  color: red;
}
 
.quiz-result.neutral {
  color: gray;
}
 
.quiz button {
  background-color: #4051b5;
  color: white;
  border: none;
  border-radius: 6px;
  padding: 6px 14px;
  cursor: pointer;
  font-size: 0.9em;
  transition: background-color 0.2s, transform 0.1s;
}
 
.quiz button:not(:disabled):hover {
  background-color: #303fa1;
  transform: translateY(-1px);
}
 
.quiz button:active {
  background-color: #202d8d;
  transform: translateY(0);
}
 
.quiz button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  box-shadow: none;
}