.container{
    display: grid;
    grid-template-rows: 2fr 4fr 0.5fr;
    grid-template-columns: 1fr 3fr;
    grid-template-areas: 
        'header header'
        'sidebar main'
        'footer footer';
}

.item1{
    grid-area:header;
}

.item2{
    grid-area: sidebar;
}

.item3{
    grid-area: main;
}

.item4{
    grid-area: footer
}