body {
    padding:0; margin:0;
}
.test {
    background:#eeeeee;
}
@media screen and (max-width: 1000px) {
    .test {
        background:#cc0000;
    }
}

@media screen and (max-width: 800px) {
    .test {
        background:#00cc00;
    }
}

@media screen and (max-width: 400px) {
    .test {
        background:#0000cc;
    }
}