body{
    background-color: #000;
}
#bg{
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    margin: auto;
    height: 100%;
    width: 100%;
    z-index: -5;
}
#userbox{
    display: block;
    position: absolute;
    height: 400px;
    width: 500px;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    margin: auto;
    background-color: #fff;
    border-bottom-left-radius: 30px;
    border-bottom-right-radius: 30px;
    border-top-left-radius: 30px;
    border-top-right-radius: 30px;
}
#userbox img{
    position: absolute;
    display: block;
    top: 30px;
    left: 0;
    right: 0;
    margin: auto;
}
#userbox input{
    position: absolute;
    display: block;
    bottom: 120px;
    left: 0;
    right: 0;
    margin: auto;
    width: 140px;
}
#userbox input::placeholder{
    position: absolute;
    width: 140px;
    top: -2px;
    text-align: center;
}
#userbox button{
    height: 30px;
    width: 80px;
    position: absolute;
    left: 0;
    right: 0;
    bottom: 40px;
    margin: auto;
    font-family: 'Noto Sans TC', sans-serif;
    background-color: aqua;
}
#userbox button:hover{
    height: 30px;
    width: 80px;
    position: absolute;
    left: 0;
    right: 0;
    bottom: 40px;
    margin: auto;
    font-family: 'Noto Sans TC', sans-serif;
    background-color: rgb(197, 255, 242);
}
#userbox button:active{
    height: 30px;
    width: 80px;
    position: absolute;
    left: 0;
    right: 0;
    bottom: 40px;
    margin: auto;
    font-family: 'Noto Sans TC', sans-serif;
    background-color: rgb(0,0, 255);
}
#loginpage{
    display: block;
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    margin: auto;
}
#chatpage{
    display: none;
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    margin: auto;
}