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

body {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100vh;
    background-color: #222;
    color: #fff;
    font-family: 'Arial', sans-serif;
    text-align: center;
    padding: 20px;
}

h1 {
    font-size: 36px;
    margin-bottom: 20px;
}

#ball-container {
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
}

#green-ball {
    width: 200px;
    height: 200px;
    background-color: green;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 0 15px rgba(0, 255, 0, 0.7);
    position: relative;
    transition: transform 0.1s ease-in-out;
}

#green-ball.shake {
    animation: shake 0.5s ease-in-out;
    animation-iteration-count: 2;
}

@keyframes shake {
    0% { transform: translate(2px, 2px) rotate(0deg); }
    10% { transform: translate(-2px, -2px) rotate(-2deg); }
    20% { transform: translate(-2px, 2px) rotate(2deg); }
    30% { transform: translate(2px, -2px) rotate(0deg); }
    40% { transform: translate(2px, 2px) rotate(2deg); }
    50% { transform: translate(-2px, -2px) rotate(-2deg); }
    60% { transform: translate(-2px, 2px) rotate(0deg); }
    70% { transform: translate(2px, -2px) rotate(2deg); }
    80% { transform: translate(2px, 2px) rotate(-2deg); }
    90% { transform: translate(-2px, -2px) rotate(0deg); }
    100% { transform: translate(2px, 2px) rotate(2deg); }
}

#answer {
    color: #fff;
    font-size: 18px;
    text-align: center;
    padding: 10px;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

button {
    padding: 10px 20px;
    font-size: 16px;
    border: none;
    border-radius: 5px;
    background-color: limegreen;
    color: #fff;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

button:hover {
    background-color: #32cd32;
}

button:active {
    background-color: #228b22;
}