Simple CSS vertical and horizontal centering (late 2015)

center.css

*{
    margin: 0;
    padding: 0;
}

body, html{
    height: 100%;
}

.container{
    display: flex;
    align-items: center;
    justify-content: center;

    height: 100%;
}

.container p{
    max-width: 50%;
    padding: 15px;
    background-color: #f1f1f1;
}