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

body {
    font-family: 'Poppins', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.container {
    max-width: 800px;
    width: 100%;
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    overflow: hidden;
}

.quiz-header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    padding: 40px 30px;
}

.quiz-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 10px;
}

.quiz-header p {
    font-size: 1.1rem;
    opacity: 0.9;
}

.quiz-container {
    position: relative;
    min-height: 500px;
}

.screen {
    display: none;
    padding: 40px 30px;
    animation: fadeIn 0.5s ease-in-out;
}

.screen.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Start Screen Styles */
.start-content {
    text-align: center;
}

.start-content h2 {
    font-size: 2rem;
    color: #333;
    margin-bottom: 20px;
}

.start-content p {
    font-size: 1.1rem;
    color: #666;
    margin-bottom: 30px;
    line-height: 1.6;
}

.quiz-info {
    display: flex;
    justify-content: space-around;
    margin: 30px 0;
    flex-wrap: wrap;
    gap: 20px;
}

.info-item {
    text-align: center;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 15px;
    min-width: 120px;
}

.info-label {
    display: block;
    font-size: 0.9rem;
    color: #666;
    margin-bottom: 5px;
}

.info-value {
    display: block;
    font-size: 1.5rem;
    font-weight: 600;
    color: #667eea;
}

/* Quiz Screen Styles */
.quiz-header-info {
    margin-bottom: 30px;
}

.progress-container {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 20px;
}

.progress-bar {
    flex: 1;
    height: 8px;
    background: #e9ecef;
    border-radius: 10px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #667eea, #764ba2);
    border-radius: 10px;
    transition: width 0.3s ease;
    width: 0%;
}

#question-counter {
    font-weight: 600;
    color: #667eea;
    white-space: nowrap;
}

.question-container {
    margin-bottom: 40px;
}

#question-text {
    font-size: 1.4rem;
    color: #333;
    margin-bottom: 30px;
    line-height: 1.5;
}

.options-container {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.option {
    padding: 20px;
    border: 2px solid #e9ecef;
    border-radius: 15px;
    cursor: pointer;
    transition: all 0.3s ease;
    background: white;
    position: relative;
    overflow: hidden;
}

.option:hover {
    border-color: #667eea;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.2);
}

.option.selected {
    border-color: #667eea;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.option.correct {
    border-color: #28a745;
    background: linear-gradient(135deg, #28a745 0%, #20c997 100%);
    color: white;
}

.option.incorrect {
    border-color: #dc3545;
    background: linear-gradient(135deg, #dc3545 0%, #e83e8c 100%);
    color: white;
}

.option input[type="radio"] {
    display: none;
}

.option-label {
    font-size: 1.1rem;
    font-weight: 500;
    cursor: pointer;
    display: block;
}

.quiz-navigation {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 20px;
}

/* Button Styles */
.btn {
    padding: 12px 30px;
    border: none;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

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

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(102, 126, 234, 0.3);
}

.btn-secondary {
    background: #6c757d;
    color: white;
}

.btn-secondary:hover:not(:disabled) {
    background: #5a6268;
    transform: translateY(-2px);
}

.btn-success {
    background: linear-gradient(135deg, #28a745 0%, #20c997 100%);
    color: white;
}

.btn-success:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(40, 167, 69, 0.3);
}

/* Results Screen Styles */
.results-content {
    text-align: center;
}

.results-content h2 {
    font-size: 2rem;
    color: #333;
    margin-bottom: 30px;
}

.score-summary {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 30px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.score-circle {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 2rem;
    font-weight: 700;
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.3);
}

.score-details {
    text-align: left;
}

.score-details p {
    font-size: 1.2rem;
    color: #333;
    margin-bottom: 10px;
}

#performance-message {
    font-weight: 600;
    color: #667eea;
}

.detailed-results {
    margin-bottom: 40px;
}

.detailed-results h3 {
    font-size: 1.5rem;
    color: #333;
    margin-bottom: 20px;
}

.question-results {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.result-item {
    background: #f8f9fa;
    border-radius: 15px;
    padding: 20px;
    text-align: left;
    border-left: 5px solid #667eea;
}

.result-item.correct {
    border-left-color: #28a745;
    background: linear-gradient(135deg, #d4edda 0%, #c3e6cb 100%);
}

.result-item.incorrect {
    border-left-color: #dc3545;
    background: linear-gradient(135deg, #f8d7da 0%, #f5c6cb 100%);
}

.result-question {
    font-weight: 600;
    color: #333;
    margin-bottom: 10px;
    font-size: 1.1rem;
}

.result-answer {
    color: #666;
    margin-bottom: 5px;
}

.result-correct {
    color: #28a745;
    font-weight: 600;
}

.result-explanation {
    font-style: italic;
    color: #666;
    margin-top: 10px;
    padding-top: 10px;
    border-top: 1px solid #dee2e6;
}

.action-buttons {
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        margin: 10px;
        border-radius: 15px;
    }
    
    .quiz-header {
        padding: 30px 20px;
    }
    
    .quiz-header h1 {
        font-size: 2rem;
    }
    
    .screen {
        padding: 30px 20px;
    }
    
    .quiz-info {
        flex-direction: column;
        align-items: center;
    }
    
    .info-item {
        min-width: 150px;
    }
    
    .score-summary {
        flex-direction: column;
        text-align: center;
    }
    
    .score-details {
        text-align: center;
    }
    
    .quiz-navigation {
        flex-direction: column;
    }
    
    .action-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .btn {
        width: 100%;
        max-width: 300px;
    }
}

@media (max-width: 480px) {
    .quiz-header h1 {
        font-size: 1.8rem;
    }
    
    #question-text {
        font-size: 1.2rem;
    }
    
    .option {
        padding: 15px;
    }
    
    .option-label {
        font-size: 1rem;
    }
    
    .score-circle {
        width: 120px;
        height: 120px;
        font-size: 1.5rem;
    }
}