.principal{
    width: 100%;
    min-height: 600px;
    padding: 0;
    margin: 0;
    display: flex;
    align-items: center;
    justify-content: center;
}
.principal article{
    width: 100%;
    max-width:900px;
    height: 250px;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 0 20px;
}
.principal article h2{
    font-size: 1.6em;
    text-align: center;
    position: relative;
}
.principal article p{
    color: #5E5E5E;
    font-size: 1.3em;
    text-align: center;
    font-family: sans-serif;
    line-height: 1.5em;
}

@media only screen and (min-width: 600px) {
    .principal article h2{
        font-size: 1.8em;
    }
    .principal article p{
        font-size: 1.35em;
    }
}