Set tab-size: 2 for GitHub code

Author: razor-x

CHANGELOG.md

@@ -7,6 +7,10 @@ This change log follows the conventions of
 
 ## [Unreleased][Unreleased]
 
+### Changed
+
+- Set `tab-size: 2` for GitHub code.
+
 ## [1.2.1] / 2016-01-21
 
 ### Fixed

stylesheets/github.sass

@@ -27,6 +27,7 @@ $font-emoji: 'Noto Color Emoji'
 
   div.file .blob-code-inner
     font-family: Monoid, #{$font-monospace}, 'Noto Emoji', #{$font-gh-monospace}
+    tab-size: 2
 
   .markdown-body
     font-family: #{$font-sans}, 'Noto Emoji', #{$font-gh-sans}, #{$font-gh-emoji}