\usepackage{imakeidx}

%% Index entries (italic font for files, preformat for code)
\newcommand{\hf}[1]{\textit{#1.h90}   \index{h90 files!#1}}
\newcommand{\ifile}[1]{\textit{#1.nc} \index{Input NetCDF files!#1.nc}}
\newcommand{\jp}[1]{\texttt{#1}       \index{Model parameters!#1}}
\newcommand{\key}[1]{\index[keys]{#1}        \texttt{\textbf{key\_#1}}}
\newcommand{\mdl}[1]{\index[modules]{#1}     \textit{#1.F90}          }
\newcommand{\ngn}[1]{\index[blocks]{#1}      \texttt{#1}              }
\newcommand{\np}[1]{ \index[parameters]{#1}  \texttt{#1}              }
\newcommand{\rou}[1]{\index[subroutines]{#1} \texttt{#1}              }

\indexsetup{toclevel=section, othercode=\small}

\makeindex[intoc=true, name=keys       , title=CPP keys                      ]
\makeindex[intoc=true, name=modules    , title=Modules                       ]
\makeindex[intoc=true, name=blocks     , title=Namelist blocks               ]
\makeindex[intoc=true, name=parameters , title=Namelist parameters, columns=3]
\makeindex[intoc=true, name=subroutines, title=Subroutines                   ]


%% Load hyperref at the end of the preamble to make it work with other pkgs
\usepackage{hyperref}                    %% hyper
\hypersetup{
%  pdftitle={\heading},
%  pdfauthor={\firstauthor and \secondauthor},
  colorlinks,
  citecolor=olive,
  linkcolor=blue,
  urlcolor=gray
}