body, html {
    height: 100%;
    margin: 0;
    font-size: 16px;
    font-family: "Arial", sans-serif;
    scroll-behavior: smooth;
    background-color: #f5f5f5;
    color: #333;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
}

.quiz-section {
    background-color: #fff;
    padding: 50px 30px;
    margin: 50px auto;
    max-width: 800px;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.quiz-section h2 {
    text-align: center;
    color: #333;
    font-size: 2.5rem;
    margin-top: 0;
    margin-bottom: 15px;
}

.quiz-section h3 {
    color: #333;
    font-size: 1.8rem;
    text-align: center;
    margin-top: 20px;
    margin-bottom: 20px;
}

.timeline-intro {
    text-align: center;
    color: #666;
    font-size: 1.1rem;
    margin-bottom: 30px;
}

.screen {
    display: none;
    animation: slideIn 0.4s ease;
}

.screen.active {
    display: block;
}

.hidden {
    display: none !important;
}

.info-box {
    color: #555;
    font-size: 1.1rem;
    line-height: 1.8;
    margin: 20px 0;
    padding: 25px;
    border-left: 5px solid #d32f2f;
    background-color: #f9f9f9;
    text-align: left;
    border-radius: 4px;
}

.timeline-button {
    background-color: #d32f2f;
    color: white;
    border: none;
    padding: 12px 35px;
    border-radius: 25px;
    font-size: 1.1rem;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
    display: block;
    margin: 30px auto 0;
}

.timeline-button:hover {
    background-color: #c71c1c;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.quiz-top {
    display: flex;
    justify-content: space-between;
    font-weight: bold;
    color: #666;
    margin-bottom: 15px;
    font-size: 1.1rem;
}

.progress-bar-container {
    width: 100%;
    height: 10px;
    background-color: #e0e0e0;
    border-radius: 5px;
    margin-bottom: 35px;
    overflow: hidden;
}

.progress-bar-fill {
    height: 100%;
    width: 0%;
    background-color: #d32f2f;
    transition: width 0.4s ease;
}

.answer-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 15px;
    margin-top: 30px;
}

.answer-btn {
    background-color: white;
    border: 2px solid #ddd;
    border-radius: 8px;
    padding: 18px 20px;
    font-size: 1.05rem;
    color: #333;
    cursor: pointer;
    text-align: left;
    font-weight: 500;
    transition: all 0.25s ease;
}

.answer-btn:hover:not(:disabled) {
    border-color: #d32f2f;
    background-color: #fff9f9;
    transform: translateX(5px);
}

.answer-btn:disabled {
    cursor: not-allowed;
}

.answer-btn.correct {
    background-color: #4caf50;
    color: white;
    border-color: #4caf50;
}

.answer-btn.wrong {
    background-color: #f44336;
    color: white;
    border-color: #f44336;
    animation: shake 0.4s ease;
}

#feedback {
    text-align: center;
    font-weight: bold;
    font-size: 1.1rem;
    min-height: 25px;
    margin-top: 20px;
}

#feedback.success {
    color: #2e7d32;
}

#feedback.error {
    color: #c62828;
}

footer {
    text-align: center;
    color: #666;
    padding: 40px 20px;
    font-size: 0.95rem;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

@media (max-width: 768px) {
    .quiz-section {
        padding: 30px 20px;
        margin: 20px 10px;
    }

    .quiz-section h2 {
        font-size: 1.8rem;
    }

    .quiz-section h3 {
        font-size: 1.4rem;
    }

    .timeline-button {
        padding: 10px 25px;
        font-size: 1rem;
    }
}