body, app{
    display: flex;
    width: 100vw;
    height: 100vh;
}

app{
   flex-direction: column; 
}

.msg{
    position: fixed;
    display: flex;
    top: 25vh;
    width: 400px;
    left: calc(50vw - 200px);
    z-index: 100;
}
.inativa{
    display: none;
}
.flex{
    display: flex;
}
.block{
    display: block;
}