Error when using a variable in a media query mixin

Error when using a variable in a media query mixin

References

Reference NO 1

http://stackoverflow.com/questions/13632752/error-when-using-a-variable-in-a-media-query-mixin

Reference NO 2

http://stackoverflow.com/questions/12181550/sass-variables-in-media-query-sass-rails-3-2-3

Reference NO 3

http://designshack.net/articles/css/sass-and-media-queries-what-you-can-and-cant-do/

Reference NO 4

http://sass-lang.com/docs/yardoc/file.SASS_REFERENCE.html

Reference NO 5

https://gist.github.com/2028061

Reference NO 6

http://thesassway.com/intermediate/responsive-web-design-in-sass-using-media-queries-in-sass-32

Reference NO 7

http://css-tricks.com/media-queries-sass-3-2-and-codekit/

Reference NO 8

http://chriseppstein.github.io/blog/2012/08/23/sass-3-2-is-released/