body {
    margin: 0;
    overflow: hidden; /* 스크롤바 제거 */
    font-family: sans-serif;
}

#bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

#ui {
    position: absolute;
    top: 10px;
    left: 10px;
    z-index: 10;
}

button {
    padding: 10px 15px;
    background-color: #ffffff;
    border: 1px solid #cccccc;
    border-radius: 5px;
    cursor: pointer;
    font-size: 16px;
    margin-right: 10px;
}

button:hover {
    background-color: #f0f0f0;
}