CSS - Mixins
http://oocss.org/spec/css-mixins.html
https://css-tricks.com/custom-user-mixins/
http://csswizardry.com/2014/11/when-to-use-extend-when-to-use-a-mixin/
https://blog.hospodarets.com/css_apply_rule
http://wynnnetherland.com/journal/css-mixins-vs-multiple-classes/
https://www.sitepoint.com/a-comprehensive-introduction-to-less-mixins/
page revision: 0, last edited: 14 Nov 2016 06:53