.tankless-quiz {
    max-width: 600px;
    margin: 0 auto;
    padding: 30px;
    background: #f8f9fa;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

.tankless-quiz h2 {
    color: #2c3e50;
    text-align: center;
    margin-bottom: 10px;
}

.quiz-subtitle {
    text-align: center;
    color: #7f8c8d;
    margin-bottom: 30px;
}

.quiz-progress {
    text-align: center;
    background: linear-gradient(90deg, #3498db, #2980b9);
    color: white;
    padding: 12px;
    border-radius: 25px;
    margin-bottom: 30px;
    font-weight: bold;
}

.quiz-question {
    background: white;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.08);
    margin-bottom: 20px;
}

.quiz-question h3 {
    color: #2c3e50;
    margin-bottom: 20px;
    font-size: 1.3em;
}

.quiz-options {
    display: flex;
    gap: 15px;
    margin-bottom: 25px;
}

.quiz-option {
    flex: 1;
    padding: 15px 20px;
    border: 3px solid #ecf0f1;
    border-radius: 10px;
    background: white;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: center;
    font-weight: 500;
}

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

.quiz-option.selected {
    background: #3498db;
    color: white;
    border-color: #2980b9;
}

.quiz-btn {
    padding: 12px 30px;
    border: none;
    border-radius: 25px;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 600;
}

.quiz-btn.primary {
    background: #27ae60;
    color: white;
}

.quiz-btn.primary:hover:not(:disabled) {
    background: #229954;
    transform: translateY(-2px);
}

.quiz-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.quiz-score {
    text-align: center;
    padding: 40px 20px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 15px;
    margin-top: 20px;
}

.quiz-score h3 {
    font-size: 2.5em;
    margin-bottom: 20px;
    color: #fff;
}

.score-excellent { color: #f39c12; }
.score-outstanding { color: #f1c40f; }
.score-perfect { color: #27ae60; }

@media (max-width: 768px) {
    .tankless-quiz {
        margin: 10px;
        padding: 20px;
    }
    
    .quiz-options {
        flex-direction: column;
    }
}