body {
    font-family: Arial, sans-serif;
    text-align: center;
    background-color: #f0f0f0;
}

#game {
    max-width: 600px;
    margin: 0 auto;
    padding: 20px;
    background-color: #c23910;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

.items, .upgrades {
    margin: 20px 0;
}

.item, .upgrade {
    padding: 10px 20px;
    margin: 5px;
    font-size: 16px;
    cursor: pointer;
}

.item {
    background-color: #0099ff;
    color: white;
}

.upgrade {
    background-color: #004718;
    color: white;
}

.item {
    width: 100px;
    height: 100px;
    margin: 10px;
    cursor: pointer;
}