This time I will talk about customizing (darkify) $\LaTeX$ writing environment. Obviously there are two parts to these: editor and PDF viewer.

Editor

The editor of my choice is TexStudio, which supports dark theme starting from v3. It can be changed under Options -> Configure TexStudio… -> General -> Appearance -> Style, Adwaita Dark (txs) is just fine for me. I guess they are adapting this colour theme from the GTK-theme in Linux desktop.

Prior to this, I was using a custom theme from pmaroco, which if I recall correctly, changes only the editor area.

PDF Viewer

I have started dark themed LaTeX experience with external viewer. However, it is not always a smooth experience. The exact same command worked fine at the beginning, but right now the forward search (from *.tex to the line in PDF) is buggy: works for some documents but not the other. I had enough of interruption with this coupling and hence now switch back to use internal viewer.

In short, if it is fine for you to change the PDF colour, I suggest go with the path of internal viewer. Otherwise, try your luck with external viewer.

Internal Viewer

With the following lines in preamble (before the line \begin{document}), you have a single point to switch between light and dark mode. The code below are separated into several files as I personally prefer to have some (false) sense of organisation in the preamble.

%% START default_preamble.tex
\usepackage{ifthen}
\newboolean{RELEASE}
\setboolean{RELEASE}{false}
%% END default_preamble.tex


%% START default_preamble_last.tex
% initially split for hyperref as there could be some problems to \input them too early
\usepackage{xcolor}
\ifthenelse{\boolean{RELEASE}} {
	\colorlet{hrefColor}{blue}
}
{
	\definecolor{page_dark}{HTML}{333333}
	\pagecolor{page_dark}
	\color{white}
	\colorlet{hrefColor}{cyan}
}

\usepackage[]{hyperref}
\hypersetup
{
	colorlinks=true,
	allcolors=hrefColor, 
}
%% END default_preamble_last.tex


%% START main.tex
\input{default_preamble.tex}
\setboolean{RELEASE}{false} % switch the boolean here
\input{default_preamble_last.tex}

\begin{document}
%...
%% END main.tex

External Viewer (SumatraPDF)

I have been using SumatraPDF as my default viewer (not editor/”signer”) for quite a while, as it is way lighter than those typical one like Acrobat Reader or Foxit Reader (though i like its fill-in options very much). I achieve this by inverting the overall colour scheme for SumatraPDF in Settings -> Advanced Options… with these 3 items:

MainWindowBackground = #555555
FixedPageUI [
	TextColor = #eeeeee
	BackgroundColor = #333333
]

As for the reverse search in SumatraPDF settings (InverseSearchCmdLine in Advanced Options…), it has to be changed to "C:\Program Files (x86)\texstudio\texstudio.exe" "%f" -line %l.

On the other hand, TexStudio as to be configured at 2 places:

  1. Options -> Configure TexStudio… -> Commands -> External PDF Viewer: 
     "C:/Program (x86) Files/SumatraPDF/SumatraPDF.exe" -reuse-instance ?am".pdf -forward-search ?c:ame" @
 dde:///"C:/Program (x86) Files/SumatraPDF/SumatraPDF.exe":SUMATRA/control/ [ForwardSearch("?am.pdf","?c:ame",@,0,0,1)]

    Try the second one if the first command does not work (according to this site, TexStudio v2.3 needs have to use the second command).

  2. Options -> Configure TexStudio… -> Build -> PDF Viewer: txs:///view-pdf-external

Sources