scss: block unused for comments

sass cleanup

remove ie hacks and compats

Disable box-shadow for radio and checkbox (#2398)

Arithmetic fix in _form.scss (#2169)

Refine search styling

Replace `fieldset` elements with `div.form-group`

Move Staticman v2 comment logic above v1 as it will be deprecated soon.

Color "skins" (#1242)

* Add YIQ Color Contrast mixin
* Remove text underline from `.btn` links
* Move YIQ variables
* Simplify button classes using YIQ color contrast mixin
  - DRY up button CSS using Sass list and YIQ color contrast mixin.
  - Move `color` and `background-color` to new `btn--primary` class instead of assinging on the default class. Removes the need to override them.
* Add `.btn--primary` to buttons that just had `.btn`
* Apply changes to `/docs`
* Add `.btn--primary` class
* Update CHANGELOG and history
* Add sample form
* Abstract colors away into Sass variables for easier themeing
* Add "dark" skin
* Replace hardcoded color with SCSS variable
* Invert Font Awesome icons' colors in author sidebar and footer
* Add Sass changes to `/docs`
* Use primary button type instead of inverse
* Add missing `!default` on `$muted-text-color`
* Add `contrast` and `sunrise` skin colors
* Add `dirt` skin color
* Add `air` skin color option
* Add `mint` skin color
* Add `btn--primary` class to Submit Comment button
* Set skin to `default`
* Document skin color options
* Add note about skin SCSS import

Close #1208 

Move SCSS partials to `/_sass/minimal-mistakes` for easier CSS customization

Merge branch 'release/3.4.0'

Merge branch 'feature/staticman-commenting' into develop

Style static comments, form, and modal

Fix typo

Merge branch 'release/3.3.7'

Merge branch 'release/3.0.0'

Merged improvement to post-index.html

Merge pull request #141 from cdodd/remove-whitespace

Remove trailing whitespace

Remove trailing whitespace

Clean up comments in Sass partials

Convert .less to .scss