html,
body {
    margin: 0;
    height: 100%;
    background: #555555;
}

.Container {
    position: absolute;
    left: 50%;
    top: 50%;
    width: 80%;
    height: 80%;
    transform: translate(-50%, -50%);
}

#errMsg,
#LoginDiv,
#QRDiv {
    display: none;
}

.header {
    font-size: 38px;
    font-weight: bold;
    text-align: center;
    line-height: 200px;
}

.input-item {
    display: block;
    width: 80%;
    margin-bottom: 20px;
    margin-left: 10%;
    border: 0;
    padding: 10px;
    border-bottom: 1px solid rgb(128, 125, 125);
    font-size: 15px;
    outline: none;
}

.input-item:placeholder {
    text-transform: uppercase;
}

.errMsg {
    position: absolute;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 80%;
    padding: 10px;
    background-color: black;
    border-radius: 5px;
    color: red;
    border: 2px solid red;
    font-size: 15px;
    outline: none;
    margin-bottom: 50px;
}

.btn {
    text-align: center;
    padding: 10px;
    width: 20%;
    margin-top: 40px;
    margin-left: 40%;
    background-image: linear-gradient(to right, #a6c1ee, #fbc2eb);
    color: #fff;
    cursor: pointer;
}

img {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}