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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    overflow: hidden;
}

.header {
    background: linear-gradient(135deg, #2c3e50, #3498db);
    color: white;
    padding: 30px;
    text-align: center;
}

.header h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
}

.score-display {
    font-size: 1.2em;
    background: rgba(255, 255, 255, 0.2);
    padding: 10px;
    border-radius: 10px;
    margin-top: 15px;
}

.quiz-container {
    padding: 30px;
}

.question-card {
    background: #f8f9fa;
    border-radius: 15px;
    padding: 25px;
    margin-bottom: 20px;
    border-left: 5px solid #3498db;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
}

.question-number {
    color: #3498db;
    font-weight: bold;
    font-size: 1.1em;
    margin-bottom: 10px;
}

.question {
    font-size: 1.3em;
    font-weight: 600;
    color: #2c3e50;
    margin-bottom: 20px;
    line-height: 1.5;
}

.options {
    display: grid;
    gap: 12px;
}

.option {
    background: white;
    border: 2px solid #e9ecef;
    border-radius: 10px;
    padding: 15px;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
}

.option:hover {
    border-color: #3498db;
    background: #f1f9ff;
    transform: translateY(-2px);
}

.option.selected {
    border-color: #3498db;
    background: #e3f2fd;
}

.option.correct {
    border-color: #27ae60;
    background: #d4edda;
    color: #155724;
}

.option.incorrect {
    border-color: #e74c3c;
    background: #f8d7da;
    color: #721c24;
}

.option.disabled {
    pointer-events: none;
    opacity: 0.7;
}

.feedback {
    margin-top: 15px;
    padding: 15px;
    border-radius: 10px;
    font-weight: 500;
    display: none;
}

.feedback.correct {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.feedback.incorrect {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.controls {
    text-align: center;
    margin-top: 30px;
}

.btn {
    background: linear-gradient(135deg, #3498db, #2980b9);
    color: white;
    border: none;
    padding: 15px 30px;
    border-radius: 10px;
    font-size: 1.1em;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    margin: 0 10px;
    margin-bottom: 25px;
}

.btn:hover {
    background: linear-gradient(135deg, #2980b9, #1f5f99);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(52, 152, 219, 0.3);
}

.btn:disabled {
    background: #bdc3c7;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.results {
    text-align: center;
    padding: 40px;
    display: none;
}

.final-score {
    font-size: 3em;
    font-weight: bold;
    color: #2c3e50;
    margin-bottom: 20px;
}

.performance {
    font-size: 1.5em;
    margin-bottom: 30px;
    padding: 20px;
    border-radius: 15px;
}

.excellent {
    background: #d4edda;
    color: #155724;
}

.good {
    background: #fff3cd;
    color: #856404;
}

.needs-improvement {
    background: #f8d7da;
    color: #721c24;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: #ecf0f1;
    border-radius: 4px;
    margin-bottom: 20px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #3498db, #2ecc71);
    transition: width 0.5s ease;
    border-radius: 4px;
}