body {
    margin: 0;
    padding: 0;
}
#container {
    width: 750px;
    margin-left: auto;
    margin-right: auto;
    border:1px solid black;
    display: grid;
    grid-template-areas: 
    "header header header header "
    "left main main right "
    "footer footer footer footer";
}
#header {
    /* height: 150px; */
    background: #9CF;
    grid-area: header;
}
#left {
    /* width: 20%; */
    /* float: left; */
    background: #ABC;
    grid-area: left;
}
#main {
    /* width: 60%; */
    /* float: left; */
    background-color: rgb(201, 114, 114);
    grid-area: main;;
}
#right {
    /* width: 20%; */
    /* float: left; */
    background: #9FF;
    grid-area: right;
}
#footer {
    /* clear: both; */
    background: #999;
    grid-area: footer;
}