Add stylesheet. (modelica#3409)

* Add stylesheet.
* Do not add specific tags.
* Add use of styelsheet
* Add vendor-style based on comments.

Co-authored-by: Malte Lenz <malte.lenz@gmail.com>
Co-authored-by: Henrik Tidefelt <henrikt@wolfram.com>

chapters/annotations.tex

@@ -42,9 +42,12 @@ \section{Documentation}\label{annotations-for-documentation}\label{documentation
   String info = "" "Description of the class";
   String revisions = "" "Revision history";
   Figure[:] figures = {}; "Simulation result figures";
+  String[:] styleSheets = {} "Style sheets for documentation";
 end Documentation;
 \end{lstlisting}
 
+The \lstinline!styleSheets! may also be given as a single string, see \cref{style-sheets}.
+
 How the tool interprets the information in \lstinline!Documentation! is unspecified.
 
 \subsection{Class Description and Revision History}\label{annotation-info-revisions}
@@ -72,6 +75,22 @@ \subsection{Class Description and Revision History}\label{annotation-info-revisi
 <a href="modelica:/MultiBody.Joints.Revolute#info">Revolute</a>
 \end{lstlisting}
 
+\subsubsection{Style Sheets}\label{style-sheets}
+
+Inside the \lstinline!Documentation! annotation, each element of the \lstinline!styleSheets! annotation array specifies a cascading style sheet.
+The style sheets are used when displaying the \lstinline!info! and \lstinline!revisions! annotations found in the \lstinline!Documentation! annotations of the package.
+The \lstinline!styleSheets! annotation is only considered for top-level packages, and applies to the entire package.
+The style sheets will be cascaded in the given order.
+Specifying just a string for \lstinline!styleSheets! has the same meaning as specifying a singleton array containing the string.
+\begin{nonnormative}
+It is recommended to use \lstinline[language=CSS]!class! and \lstinline[language=CSS]!id! selectors with a \lstinline[language=CSS]!$NameOfLibrary$-! prefix to avoid collisions when the content is included in a larger context.
+\end{nonnormative}
+The style sheet rules should not use type or universal selectors, due to possible interference with tool-specific styling.
+
+Vendors should use a \lstinline[language=CSS]!$NameOfVendor$-! prefix to style vendor generated HTML content surrounding the user provided documentation.
+If tools want to give users (of that tool) the possibility to override the tool-specific CSS they can document that.
+The prefix is used to avoid this happening by accident.
+
 \subsection{Figures}\label{annotations-for-figures}\label{figures}
 
 Inside the \lstinline!Documentation! annotation, each element of the \lstinline!figures! annotation array has the following content:

mlsshared.sty

@@ -184,6 +184,17 @@
         include,pragma,undef,warning}
 }[keywords,comments,strings,directives]
 
+\lstdefinelanguage{CSS}{
+      keywords={},  
+      sensitive=true,
+      morecomment=[l]{//},
+      morecomment=[s]{/*}{*/},
+      morestring=[b]',
+      morestring=[b]",
+      alsoletter={:},
+      alsodigit={-}
+}
+
 \lstset{%
   backgroundcolor=\color{white},   % choose the background color
   mathescape=true,