Doc:Install or build>Build>Windows: Improve the section on building with Ninja

hugo/content/installation/building/windows/index.md

@@ -79,12 +79,6 @@ Create the folders
 
 and paste the corresponding content from the ZIP files in those two folders.
 
-> #### *Additional: Ninja*
->
-> The time to compile can be significantly improved, depending on the hardware, if Ninja is used as a build system.
-> To download Ninja, go to [ninja-build.org](https://ninja-build.org) and download the Windows binary via GitHub.
-> Add the binaries directory in your `PATH`, f.e. `C:\Program Files\ninja`.
-
 #### System Enviroment Variables
 
 After those installations your `PATH` should contain
@@ -118,30 +112,38 @@ cmake -G "Visual Studio 16 2019" -A x64 -T host=x64 -DLIB_MAN=OFF -DQTDIR="$QTDI
 
 cmake --build . --config Release
 
+ctest -C Release --parallel 8 --output-on-failure
+```
+<br>
+
+<details> <summary> <b> Build with Ninja (Experimental) </b> </summary>
+
+Compilation might be accelerated if Ninja is used as a build system.
+Download the Ninja binary for Windows from [ninja-build.org](https://ninja-build.org). Add the binaries to a directory in your `PATH`; e.g. `C:\Program Files\ninja`.
+
+To use Ninja as the build system, the compilation cannot be performed in a PowerShell but in the Visual Studio Shell **x64 Native Tools Command Prompt for VS 2019** which you can search for in the start menu.
+
+Use the following commands to build BornAgain:
+```
+set OPTLIBS=C:/opt/x64
+set FFTW3_INCLUDE_DIR=%OPTLIBS%/include
+set FFTW3_LIB=%OPTLIBS%/lib/libfftw3-3.lib
+set QTDIR=C:/Qt/current/msvc2019_64
+set QTCMake_DIR=%QTDIR%/lib/cmake
+set BUILD_DIR=buildnj
+
+mkdir "%BUILD_DIR%"
+cd "%BUILD_DIR%"
+
+cmake --version
+
+cmake -G "Ninja" -DCMAKE_BUILD_TYPE=Release -DQTDIR="%QTDIR%" -DQt5_DIR="%QTCMake_DIR%/Qt5" -DQt5Test_DIR="%QTCMake_DIR%/Qt5Test" -DFFTW3_INCLUDE_DIR="%FFTW3_INCLUDE_DIR%" -DFFTW3_LIBRARY="%FFTW3_LIB%" -DCMAKE_INCLUDE_PATH="%OPTLIBS%/include" -DCMAKE_LIBRARY_PATH="%OPTLIBS%/lib" -DLIB_MAN=OFF -DCMAKE_C_COMPILER="cl.exe" -DCMAKE_CXX_COMPILER="cl.exe" -B. ..
+
+echo "## BUILD START:" %time%
+cmake --build . --config Release --parallel 8
+
+echo "## BUILD END:" %time%
 ctest -C Release --parallel 8 --output-on-failure
 ```
 
-> #### *Additional: Build with Ninja* (Experimental)
->
-> To use Ninja as the build system, the compilation cannot be performed in a PowerShell but in the Visual Studio Shell **x64 Native Tools Command Prompt for VS 2019** which you can serach for in the start menu.
-> ```
-> set OPTLIBS=C:/opt/x64
-> set FFTW3_INCLUDE_DIR=%OPTLIBS%/include
-> set FFTW3_LIB=%OPTLIBS%/lib/libfftw3-3.lib
-> set QTDIR=C:/Qt/current/msvc2019_64
-> set QTCMake_DIR=%QTDIR%/lib/cmake
-> set BUILD_DIR=buildnj
->
-> mkdir "%BUILD_DIR%"
-> cd "%BUILD_DIR%"
->
-> cmake --version
->
->cmake -G "Ninja" -DCMAKE_BUILD_TYPE=Release -DQTDIR="%QTDIR%" -DQt5_DIR="%QTCMake_DIR%/Qt5" -DQt5Test_DIR="%QTCMake_DIR%/Qt5Test" -DFFTW3_INCLUDE_DIR="%FFTW3_INCLUDE_DIR%" -DFFTW3_LIBRARY="%FFTW3_LIB%" -DCMAKE_INCLUDE_PATH="%OPTLIBS%/include" -DCMAKE_LIBRARY_PATH="%OPTLIBS%/lib" -DLIB_MAN=OFF -DCMAKE_C_COMPILER="cl.exe" -DCMAKE_CXX_COMPILER="cl.exe" -B. ..
->
->echo "## BUILD START:" %time%
->cmake --build . --config Release --parallel 8
->
->echo "## BUILD END:" %time%
->ctest -C Release --parallel 8 --output-on-failure
-> ```
+</details>