You've assigned `grid-area: main` to the content but the parent grid doesn’t define "main" in its grid-template-areas; the browser creates an implicit grid row/column to satisfy the placement, and this ends up being below the defined areas. Thus requiring 1 page blank space to scroll down.

You can investigate the `<div class="main-content">` in Dev Tools by toggling the 'grid-area' CSS attribute off; that fixes the display.