body {
  font-family: Arial, sans-serif;
  background: #f4f4f4;
  margin: 0;
  padding: 0;
}
#app {
  max-width: 500px;
  margin: 40px auto;
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  padding: 24px;
}
input, select, button {
  font-size: 1rem;
  margin: 8px 0;
  padding: 8px;
  width: 100%;
  box-sizing: border-box;
}
.progress-bar {
  height: 16px;
  background: #eee;
  border-radius: 8px;
  overflow: hidden;
  margin: 16px 0;
}
.progress-bar-inner {
  height: 100%;
  background: #4caf50;
  width: 0;
  transition: width 0.3s;
}
.quiz-option {
  display: block;
  background: #f9f9f9;
  border: 1px solid #ddd;
  border-radius: 4px;
  margin: 8px 0;
  padding: 10px;
  cursor: pointer;
  transition: background 0.2s, border 0.2s;
}
.quiz-option.correct {
  background: #c8e6c9;
  border-color: #388e3c;
}
.quiz-option.incorrect {
  background: #ffcdd2;
  border-color: #d32f2f;
}
@media (max-width: 600px) {
  #app {
    padding: 10px;
    max-width: 100%;
  }
}