use a flat light-mode doxygen theme

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "docs/doxygen_theme_flat_design"]
+	path = docs/doxygen_theme_flat_design
+	url = https://github.com/kcwongjoe/doxygen_theme_flat_design.git

docs/Doxyfile.in

@@ -130,7 +130,8 @@ FILE_PATTERNS          = *.cpp \
                          *.md \
                          *.py
 RECURSIVE              = YES
-EXCLUDE                = @CMAKE_CURRENT_SOURCE_DIR@/example \
+EXCLUDE                = @CMAKE_CURRENT_SOURCE_DIR@/docs \
+                         @CMAKE_CURRENT_SOURCE_DIR@/example \
                          @CMAKE_CURRENT_SOURCE_DIR@/platform \
                          @CMAKE_CURRENT_SOURCE_DIR@/test
 EXCLUDE_SYMLINKS       = NO
@@ -170,21 +171,17 @@ HTML_OUTPUT            = html
 HTML_FILE_EXTENSION    = .html
 HTML_HEADER            = @CMAKE_CURRENT_SOURCE_DIR@/docs/doxygen_files/header.html
 HTML_FOOTER            = @CMAKE_CURRENT_SOURCE_DIR@/docs/doxygen_files/footer.html
-HTML_STYLESHEET        =
-HTML_EXTRA_STYLESHEET  = @CMAKE_CURRENT_SOURCE_DIR@/docs/doxygen_files/custom.css
+HTML_STYLESHEET        = @CMAKE_CURRENT_SOURCE_DIR@/docs/doxygen_files/doxygen.css
+HTML_EXTRA_STYLESHEET  = @CMAKE_CURRENT_SOURCE_DIR@/docs/doxygen_theme_flat_design/src/doxygen-style.css
 HTML_EXTRA_FILES       =
 HTML_COLORSTYLE_HUE    = 220
 HTML_COLORSTYLE_SAT    = 100
 HTML_COLORSTYLE_GAMMA  = 80
 HTML_TIMESTAMP         = NO
 HTML_DYNAMIC_MENUS     = YES
-HTML_DYNAMIC_SECTIONS  = NO
+HTML_DYNAMIC_SECTIONS  = YES
 HTML_INDEX_NUM_ENTRIES = 100
 GENERATE_DOCSET        = NO
-DOCSET_FEEDNAME        = "Doxygen generated docs"
-DOCSET_BUNDLE_ID       = org.doxygen.Project
-DOCSET_PUBLISHER_ID    = org.doxygen.Publisher
-DOCSET_PUBLISHER_NAME  = Publisher
 GENERATE_HTMLHELP      = NO
 CHM_FILE               =
 HHC_LOCATION           =
@@ -201,7 +198,6 @@ QHP_CUST_FILTER_ATTRS  =
 QHP_SECT_FILTER_ATTRS  =
 QHG_LOCATION           =
 GENERATE_ECLIPSEHELP   = NO
-ECLIPSE_DOC_ID         = org.doxygen.Project
 DISABLE_INDEX          = NO
 GENERATE_TREEVIEW      = NO
 ENUM_VALUES_PER_LINE   = 4
@@ -226,53 +222,22 @@ EXTRA_SEARCH_MAPPINGS  =
 # Configuration options related to the LaTeX output
 #---------------------------------------------------------------------------
 GENERATE_LATEX         = NO
-LATEX_OUTPUT           = latex
-LATEX_CMD_NAME         =
-MAKEINDEX_CMD_NAME     = makeindex
-LATEX_MAKEINDEX_CMD    = makeindex
-COMPACT_LATEX          = NO
-PAPER_TYPE             = a4
-EXTRA_PACKAGES         =
-LATEX_HEADER           =
-LATEX_FOOTER           =
-LATEX_EXTRA_STYLESHEET =
-LATEX_EXTRA_FILES      =
-PDF_HYPERLINKS         = YES
-USE_PDFLATEX           = YES
-LATEX_BATCHMODE        = NO
-LATEX_HIDE_INDICES     = NO
-LATEX_BIB_STYLE        = plain
-LATEX_TIMESTAMP        = NO
-LATEX_EMOJI_DIRECTORY  =
 #---------------------------------------------------------------------------
 # Configuration options related to the RTF output
 #---------------------------------------------------------------------------
 GENERATE_RTF           = NO
-RTF_OUTPUT             = rtf
-COMPACT_RTF            = NO
-RTF_HYPERLINKS         = NO
-RTF_STYLESHEET_FILE    =
-RTF_EXTENSIONS_FILE    =
 #---------------------------------------------------------------------------
 # Configuration options related to the man page output
 #---------------------------------------------------------------------------
 GENERATE_MAN           = NO
-MAN_OUTPUT             = man
-MAN_EXTENSION          = .3
-MAN_SUBDIR             =
-MAN_LINKS              = NO
 #---------------------------------------------------------------------------
 # Configuration options related to the XML output
 #---------------------------------------------------------------------------
 GENERATE_XML           = NO
-XML_OUTPUT             = xml
-XML_PROGRAMLISTING     = YES
-XML_NS_MEMB_FILE_SCOPE = NO
 #---------------------------------------------------------------------------
 # Configuration options related to the DOCBOOK output
 #---------------------------------------------------------------------------
 GENERATE_DOCBOOK       = NO
-DOCBOOK_OUTPUT         = docbook
 #---------------------------------------------------------------------------
 # Configuration options for the AutoGen Definitions output
 #---------------------------------------------------------------------------
@@ -284,9 +249,6 @@ GENERATE_AUTOGEN_DEF   = NO
 # Configuration options related to the Perl module output
 #---------------------------------------------------------------------------
 GENERATE_PERLMOD       = NO
-PERLMOD_LATEX          = NO
-PERLMOD_PRETTY         = YES
-PERLMOD_MAKEVAR_PREFIX =
 #---------------------------------------------------------------------------
 # Configuration options related to the preprocessor
 #---------------------------------------------------------------------------

docs/doxygen_files/custom.css

@@ -1,28 +0,0 @@
-ul.sm-dox
-{
-  background-image: inherit;
-  background-color: #DFE5F1;
-}
-
-h2.memtitle
-{
-  background-image: inherit;
-}
-
-div.navpath ul
-{
-  background-image: inherit;
-  background-color: #DFE5F1;
-}
-
-div#MSearchBox
-{
-  border-radius: inherit;
-  box-shadow: inherit;
-}
-
-input#MSearchField
-{
-  height: inherit;
-  width: inherit;
-}

docs/doxygen_theme_flat_design

@@ -0,0 +1 @@
+Subproject commit 7be08cbe5531f60607dffb2f8f76f6c070a9c81b