html, body, #mainForm {
    height: 100%;
    width: 100%;
}

div.body {
    display: table;
    height: 100%;
    width: 100%;
}

header, div.main {
    display: table-row;
}

div.main {
    height: 100%;
}

div.main > .content > .container {
    display: table;
    height: 100%;
}