Layout 3 Rows

layout.css

html, body {
    padding: 0;
    margin: 0;
    height: 100%;
}

.wrapper {
    display: table;
    width: 100%;
    height: 100%;
}

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

.header, .footer {
    height: 40px;
    background: salmon;
}

.main {
    background: lightyellow;
}