body {
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background: grey;
}

.quiz-container {
    background: #fff;
    padding: 20px 30px;
    border-radius: 10px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
    max-width: 400px;
    width: 100%;
}

h2 {
    margin-bottom: 15px;
    text-align: center;
    /* Center the question */
}

#answer-buttons {
    min-height: 200px;
    /* Reserve space so layout doesn’t jump */
}

.btn {
    display: block;
    width: 100%;
    margin: 8px 0;
    padding: 10px;
    background: #3498db;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background 0.3s;
}

.btn:hover {
    background: black;
}

#next-btn {
    margin-top: 15px;
    background: black;
    opacity: 0;
    /* Start hidden */
    visibility: hidden;
    transition: opacity 0.5s ease;
    /* Fade effect */
}

#next-btn.show {
    opacity: 1;
    visibility: visible;
}