feat: news media offset via core-styles mixin

[wesleyboar]

Overview

Offset news media —

• main image (atop content)
• secondary images, et cetera (in content)

— via Core-Styles mixin offset-content.

Related

• RT #37827
• requires feat: mixin offset-content Core-Styles#577
• fixed by fix: incorrect media query syntax in x-news.css #1062

Changes

• changed raw style to mixin for content media offset
• added offset mixins that themselves use Core-Styles offset mixin
• changed raw style to mixin for main media offset

Testing

0. Have:
   • news article with image
   • thumbnail option of full-width i.e. Width: 0
   • thumbnail option of set width i.e. Width: 300
1. Set main image to thumbnail option full-width.
   • On wide screen, image is as wide as content.
   • On narrow screen, image is as wide as content.
2. Set main image to thumbnail option set width.
   • On wide screen, image is offset to the right.
   • On narrow screen, image is floated to the right.

UI

full-width.image.mov

max-width.image.mov