[RFM] Refactor: Remove unnecessary nesting

[lewiscowper]

I heard somewhere that it may be harmful.

Files with nesting to be removed:

• [x] _blog.scss
• [x] _category.scss
• [x] _colour.scss
• [x] _events.scss
• [x] _footer.scss
• [x] _layout.scss
• [x] _modules.scss
• [x] _nav.scss
• [x] _teaser-index.scss
• [x] _typo.scss

[gr2m]

wow, just saluting to the huge amounts of work you put into this <3