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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    /* 👇 Background Image + Gradient Overlay */
    background: linear-gradient(rgba(0,0,0,0.4), rgba(0,0,0,0.4)),
                url("project.jpg");
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    background-attachment: fixed;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}


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

.screen {
    display: none;
    min-height: 500px;
}

.screen.active {
    display: block;
}

/* Welcome Screen Styles */
.welcome-content {
    text-align: center;
    padding: 60px 40px;
}

.welcome-content h1 {
    font-size: 2.5rem;
    color: #333;
    margin-bottom: 20px;
    font-weight: 700;
}

.welcome-content p {
    font-size: 1.2rem;
    color: #666;
    margin-bottom: 40px;
}

.quiz-info {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.info-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.icon {
    font-size: 2rem;
}

.info-item span:last-child {
    color: #666;
    font-weight: 500;
}

/* Button Styles */
.btn {
    padding: 15px 30px;
    border: none;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.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: #f8f9fa;
    color: #333;
    border: 2px solid #e9ecef;
}

.btn-secondary:hover:not(:disabled) {
    background: #e9ecef;
}

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

/*  For Quiz Screen Styles */
.quiz-header {
    padding: 30px 40px 20px;
    border-bottom: 1px solid #e9ecef;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.progress-container {
    flex: 1;
    margin-right: 20px;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: #e9ecef;
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 10px;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    transition: width 0.3s ease;
    width: 0%;
}

.question-counter {
    font-weight: 600;
    color: #666;
}

.timer {
    background: #ff6b6b;
    color: white;
    padding: 10px 20px;
    border-radius: 50px;
    font-weight: 700;
    font-size: 1.1rem;
    min-width: 60px;
    text-align: center;
}

.timer.warning {
    background: #ff9f43;
    animation: pulse 1s infinite;
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

.quiz-content {
    padding: 40px;
}

.question-text {
    font-size: 1.5rem;
    color: #333;
    margin-bottom: 30px;
    line-height: 1.6;
}

.options-container {
    display: grid;
    gap: 15px;
}

.option {
    padding: 20px;
    border: 2px solid #e9ecef;
    border-radius: 15px;
    cursor: pointer;
    transition: all 0.3s ease;
    background: white;
    display: flex;
    align-items: center;
    gap: 15px;
}

.option:hover {
    border-color: #667eea;
    background: #f8f9ff;
}

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

.option-letter {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: #e9ecef;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    flex-shrink: 0;
}

.option.selected .option-letter {
    background: rgba(255, 255, 255, 0.2);
    color: white;
}

.option-text {
    flex: 1;
    font-size: 1.1rem;
}

.quiz-footer {
    padding: 20px 40px 30px;
    display: flex;
    justify-content: space-between;
}

/*  For Results Screen Styles */
.results-content {
    text-align: center;
    padding: 60px 40px;
}

.score-circle {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 30px;
    position: relative;
}

.score-text {
    color: white;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.score-percentage {
    font-size: 3rem;
    font-weight: 700;
}

.score-label {
    font-size: 1.2rem;
    opacity: 0.9;
}

.result-title {
    font-size: 2rem;
    color: #333;
    margin-bottom: 15px;
}

.result-message {
    font-size: 1.2rem;
    color: #666;
    margin-bottom: 40px;
}

.result-stats {
    display: flex;
    justify-content: center;
    gap: 40px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    color: #333;
}

.stat-label {
    color: #666;
    font-weight: 500;
}

.result-actions {
    display: flex;
    gap: 20px;
    justify-content: center;
    flex-wrap: wrap;
}

/*  For Review Screen Styles */
.review-content {
    padding: 40px;
}

.review-content h2 {
    text-align: center;
    margin-bottom: 30px;
    color: #333;
}

.review-container {
    margin-bottom: 30px;
}

.review-item {
    margin-bottom: 30px;
    padding: 25px;
    border-radius: 15px;
    background: #f8f9fa;
}

.review-question {
    font-weight: 600;
    margin-bottom: 15px;
    color: #333;
}

.review-options {
    display: grid;
    gap: 10px;
    margin-bottom: 15px;
}

.review-option {
    padding: 10px 15px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    gap: 10px;
}

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

.review-option.wrong {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.review-option.user-selected {
    font-weight: 600;
}

.review-result {
    font-weight: 600;
    padding: 10px;
    border-radius: 8px;
    text-align: center;
}

.review-result.correct {
    background: #d4edda;
    color: #155724;
}

.review-result.wrong {
    background: #f8d7da;
    color: #721c24;
}

/* Responsive Design which means we adjust accordingly the device width */
@media (max-width: 768px) {
    .quiz-container {
        margin: 10px;
        border-radius: 15px;
    }

    .welcome-content {
        padding: 40px 30px;
    }

    .welcome-content h1 {
        font-size: 2rem;
    }

    .quiz-info {
        gap: 20px;
    }

    .quiz-header {
        padding: 20px 30px 15px;
        flex-direction: column;
        gap: 15px;
    }

    .progress-container {
        margin-right: 0;
        width: 100%;
    }

    .quiz-content {
        padding: 30px;
    }

    .question-text {
        font-size: 1.3rem;
    }

    .quiz-footer {
        padding: 15px 30px 25px;
    }

    .results-content {
        padding: 40px 30px;
    }

    .score-circle {
        width: 150px;
        height: 150px;
    }

    .score-percentage {
        font-size: 2.5rem;
    }

    .result-stats {
        gap: 25px;
    }

    .result-actions {
        flex-direction: column;
        align-items: center;
    }

    .btn {
        width: 100%;
        max-width: 250px;
    }
}

@media (max-width: 480px) {
    .welcome-content h1 {
        font-size: 1.8rem;
    }

    .quiz-info {
        flex-direction: column;
        gap: 15px;
    }

    .question-text {
        font-size: 1.2rem;
    }

    .option {
        padding: 15px;
    }

    .option-text {
        font-size: 1rem;
    }
}