--- a/style.sty	Wed Oct 21 13:31:56 2015 +0100
+++ b/style.sty	Wed Oct 21 22:07:46 2015 +0100
@@ -5,10 +5,18 @@
 \usepackage{amssymb}
 \usepackage{amsmath}
 \usepackage{menukeys}
+\@ifpackageloaded{hyperref}{}{\usepackage{hyperref}}
+
 \definecolor{darkblue}{rgb}{0,0,0.6}
-\usepackage[colorlinks=true,urlcolor=darkblue,linkcolor=darkblue]{hyperref}
+\hypersetup{colorlinks=true}
+\hypersetup{linkcolor=darkblue}
+\hypersetup{urlcolor=darkblue}
+
 
-\newcommand{\dn}{\stackrel{\mbox{\scriptsize def}}{=}}%
+\ifx\foobar\undefined \else
+  \newcommand{\dn}{\stackrel{\mbox{\scriptsize def}}{=}}%
+\fi
+
 \definecolor{codegray}{gray}{0.9}
 
 \newcommand\grid[1]{%