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

body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background-color: #f5f5f5;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  padding: 20px;
}

.container {
  background-color: white;
  border-radius: 10px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  max-width: 600px;
  width: 100%;
  padding: 40px;
}

h1 {
  color: #333;
  text-align: center;
  margin-bottom: 30px;
  font-size: 28px;
}

.start-screen,
.quiz-screen,
.result-screen {
  display: none;
}

.start-screen.active,
.quiz-screen.active,
.result-screen.active {
  display: block;
}

.start-screen {
  text-align: center;
}

.start-screen p {
  color: #666;
  font-size: 18px;
  margin-bottom: 30px;
}

.question-header {
  color: #666;
  font-size: 14px;
  margin-bottom: 20px;
}

.question-title {
  color: #333;
  font-size: 20px;
  margin-bottom: 25px;
  font-weight: 500;
}

.options {
  margin-bottom: 30px;
}

.option {
  background-color: #f9f9f9;
  border: 2px solid #e0e0e0;
  border-radius: 8px;
  padding: 15px;
  margin-bottom: 12px;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
}

.option:hover {
  border-color: #999;
  background-color: #f0f0f0;
}

.option.selected {
  border-color: #555;
  background-color: #e8e8e8;
}

.option input[type="radio"] {
  margin-right: 12px;
  width: 18px;
  height: 18px;
  cursor: pointer;
}

.option label {
  cursor: pointer;
  flex: 1;
  color: #333;
  font-size: 16px;
}

button {
  background-color: #555;
  color: white;
  border: none;
  padding: 12px 30px;
  font-size: 16px;
  border-radius: 6px;
  cursor: pointer;
  transition: background-color 0.3s ease;
  width: 100%;
  font-weight: 500;
}

button:hover {
  background-color: #333;
}

button:disabled {
  background-color: #ccc;
  cursor: not-allowed;
}

.result-screen {
  text-align: center;
}

.score-display {
  font-size: 48px;
  color: #333;
  margin: 30px 0;
  font-weight: bold;
}

.result-message {
  font-size: 20px;
  color: #666;
  margin-bottom: 30px;
}

.percentage {
  font-size: 24px;
  color: #888;
  margin-bottom: 40px;
}