add "Floatage" widget

This widget floats block left or right mainly for images.
use `em` unit for "Posts" date

`5em` reflects 10 characters ("XXX nn, nnnn" minus to whitespaces).
add styles for image on "Posts"

This style enables displaying reference image of latest update on home page.
move local variable more specific level
add hanging label to "Posts" on large screen
forget previous changes to "Posts"

* heading label
* images
follow HTML changes
place "Site Navigation" top on small screen

Reduce white spaces, but keep readability.
add "Section Header" component

* align center on small screen
* add simple line label
* adjust "Article Footer" placement
calculate sizes with "Logo" sizes
lighten `blockquote` text
version 6.43.11