body {
  background-color: lightblue;
  color: black;
  font-family: Verdana;
}

.container {
  display: grid;
  grid-template-areas:
    "header header header"
    "menu content extra"
    "footer footer footer";
  grid-template-columns: 20% 60% 20%;
  gap: 3px;
  background-color: dodgerblue;
  padding: 5px;
  width: 1400px;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}
.container div {
  background-color: white;
  padding: 10px;
}
.container .header {
  grid-area: header;
  text-align: center;
}
.container .menu {
  grid-area: menu;
}
.container .content {
  grid-area: content;
}

.container .extra {
  grid-area: extra;
}

.container .footer {
  grid-area: footer;
  text-align: center;  
}