Add a `date` to the document frontmatter

Define margins in parent elements#

Margins is a relation between elements, it is not a property of a single element, it should be defined it parent element for all of its children

This is what the Stack element does

Stack layouts some elements vertically or horizontally

Asymmetrical spacing using Spacer component

A Spacer component is just a box with flexGrow set to 1

To make a component