body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    background-color: #f5f7fa;
    line-height: 1.6;
}

.header {
    text-align: center;
    margin-bottom: 30px;
    background: white;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.quiz-selector {
    background: white;
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 20px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.quiz-container {
    background: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    display: none;
}

.quiz-container.active {
    display: block;
}

.question {
    margin-bottom: 25px;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 8px;
    border-left: 4px solid #007bff;
}

.question h3 {
    margin-top: 0;
    color: #333;
}

.options {
    list-style: none;
    padding: 0;
}

.option {
    margin: 10px 0;
    padding: 12px 15px;
    background: white;
    border: 2px solid #e9ecef;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s;
}

.option:hover {
    border-color: #007bff;
    background: #f8f9ff;
}

.option.correct {
    border-color: #28a745;
    background: #d4edda;
    color: #155724;
}

.option.incorrect {
    border-color: #dc3545;
    background: #f8d7da;
    color: #721c24;
}

.option.disabled {
    cursor: not-allowed;
    opacity: 0.7;
}

.feedback {
    margin-top: 15px;
    padding: 10px 15px;
    border-radius: 6px;
    font-weight: 500;
}

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

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

.next-btn, .start-btn, .restart-btn {
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 16px;
    margin-top: 20px;
    transition: background 0.2s;
    flex: 1;
}

.next-btn, .start-btn {
    background: #007bff;
}

.next-btn:hover, .start-btn:hover {
    background: #0056b3;
}

.restart-btn {
    background: #6c757d;
}

.restart-btn:hover {
    background: #5a6268;
}

.next-btn:disabled, .start-btn:disabled {
    background: #6c757d;
    cursor: not-allowed;
}

.progress {
    margin-bottom: 20px;
    text-align: center;
    color: #666;
}

.selector-btn {
    background: #6c757d;
    color: white;
    border: none;
    padding: 10px 20px;
    margin: 5px;
    border-radius: 6px;
    cursor: pointer;
    transition: background 0.2s;
}

.selector-btn:hover {
    background: #5a6268;
}

.selector-btn.active {
    background: #007bff;
}

.start-btn {
    background: #28a745;
    display: block;
    width: 100%;
    margin-top: 15px;
}

.start-btn:hover {
    background: #218838;
}

/* Button container for better mobile layout */
.button-container {
    display: flex;
    gap: 10px;
    margin-top: 20px;
    flex-wrap: wrap;
}

/* Mobile responsiveness */
@media (max-width: 768px) {
    body {
        padding: 15px;
    }
    
    .header {
        padding: 15px;
    }
    
    .quiz-selector, .quiz-container {
        padding: 20px;
    }
    
    .question {
        padding: 15px;
    }
    
    /* Stack buttons vertically on mobile */
    .button-container {
        flex-direction: column;
        gap: 10px;
    }
    
    .next-btn, .restart-btn {
        width: 100%;
        margin-left: 0;
        margin-top: 0;
    }
    
    /* Ensure selector buttons wrap nicely */
    .quiz-selector {
        text-align: center;
    }
    
    .selector-btn {
        margin: 3px;
        padding: 8px 16px;
        font-size: 14px;
    }
}

@media (max-width: 480px) {
    body {
        padding: 10px;
    }
    
    .header, .quiz-selector, .quiz-container {
        padding: 15px;
    }
    
    .question {
        padding: 12px;
    }
    
    .selector-btn {
        display: block;
        width: 100%;
        margin: 5px 0;
    }
}