Update on October 05, 2020: Added instructions near the end to make the tutorial work for singular pages of Custom Post Types.
This members-only tutorial provides the steps to display a grid of child Pages (if present) when viewing a static Page in Oxygen.
A parent Page:
Another parent Page:
A Page that does not contain at least one subpage:
We shall set up the Template that applies to all Pages to show the title, content and then the list of all Pages using a Repeater filtered via pre_get_posts for setting the parent to the current Page ID.
3 lines of code and we will have the Pages list appear as a responsive grid using the magic of CSS Grid.
For ensuring that the subpages grid appears only if the current Page has at least 1 child Page, we shall create a custom function and use it via the built-in Dynamic Data condition.
Let us register a custom image size for the images in the child Pages grid.