Edit in JSFiddle

var map = new GMaps({
    div: '#map',
    lat: -12.043333,
    lng: -77.028333
});
<div id="map"></div>
html,
body,
#map {
    display: block;
    width: 100%;
    height: 100%;
}

#map {
    background: #58B;
}

External resources loaded into this fiddle: