body {
    background-color: lightblue;
    text-align: center;
    padding: 60% 0;
}

@media screen and (min-width: 400px) {
    body {
        background-color: lightgreen;
        padding:30% 0;
    }
}

@media screen and (min-width: 800px) {
    body {
        background-color: lavender;
        padding:200px 0; 
    }
}
.centered{
	max-width: 275px;
	margin: 20px auto;
	width: 90%;
	text-align: center;
}
footer {
    position: absolute;
    left: 0;
    bottom: 0;
    height: 30px;
    width: 100%;
    overflow: hidden;
}