calculations. /* declare a grid and set up a 10 column grid with gutters */ .container { width: 90%; margin: 0 auto 0 auto; display: grid; grid-template-columns: [col] 4.25fr repeat(9, [gutter] 1fr [col] 4.25fr ) [gutter]; grid-template-rows: auto repeat(5, 100px); } /* boxes positioned like so */ /* heading in row 1 full width */ h1 { grid-column: col / span col 10; grid-row: 1 / 2; } /* left hand sidebar */ .ag1 { grid-column: col / span gutter 2; grid-row: 2 / 3; }