diff --git a/Source/NimbleCommander/NimbleCommander/Resources/SyntaxHighlighting/Main.json b/Source/NimbleCommander/NimbleCommander/Resources/SyntaxHighlighting/Main.json
index eb0832d0e..edcebed7c 100644
--- a/Source/NimbleCommander/NimbleCommander/Resources/SyntaxHighlighting/Main.json
+++ b/Source/NimbleCommander/NimbleCommander/Resources/SyntaxHighlighting/Main.json
@@ -15,6 +15,16 @@
             "settings": "JSON.json",
             "filemask": "*.json"
         },
+        {
+            "name": "Markdown",
+            "settings": "Markdown.json",
+            "filemask": "*.md, *.markdown"
+        },
+        {
+            "name": "XML",
+            "settings": "XML.json",
+            "filemask": "*.xml, *.plist"
+        },
         {
             "name": "YAML",
             "settings": "YAML.json",
diff --git a/Source/NimbleCommander/NimbleCommander/Resources/SyntaxHighlighting/Markdown.json b/Source/NimbleCommander/NimbleCommander/Resources/SyntaxHighlighting/Markdown.json
new file mode 100644
index 000000000..e6c04299b
--- /dev/null
+++ b/Source/NimbleCommander/NimbleCommander/Resources/SyntaxHighlighting/Markdown.json
@@ -0,0 +1,31 @@
+{
+    "lexer": "markdown",
+    "wordlists": [],
+    "properties": {
+        "lexer.markdown.header.eolfill": "1"
+    },
+    "mapping": {
+        "SCE_MARKDOWN_DEFAULT": "default",
+        "SCE_MARKDOWN_LINE_BEGIN": "default",
+        "SCE_MARKDOWN_STRONG1": "number",
+        "SCE_MARKDOWN_STRONG2": "number",
+        "SCE_MARKDOWN_EM1": "comment",
+        "SCE_MARKDOWN_EM2": "comment",
+        "SCE_MARKDOWN_HEADER1": "keyword",
+        "SCE_MARKDOWN_HEADER2": "keyword",
+        "SCE_MARKDOWN_HEADER3": "keyword",
+        "SCE_MARKDOWN_HEADER4": "keyword",
+        "SCE_MARKDOWN_HEADER5": "keyword",
+        "SCE_MARKDOWN_HEADER6": "keyword",
+        "SCE_MARKDOWN_PRECHAR": "default",
+        "SCE_MARKDOWN_ULIST_ITEM": "preprocessor",
+        "SCE_MARKDOWN_OLIST_ITEM": "preprocessor",
+        "SCE_MARKDOWN_BLOCKQUOTE": "identifier",
+        "SCE_MARKDOWN_STRIKEOUT": "operator",
+        "SCE_MARKDOWN_HRULE": "default",
+        "SCE_MARKDOWN_LINK": "string",
+        "SCE_MARKDOWN_CODE": "string",
+        "SCE_MARKDOWN_CODE2": "string",
+        "SCE_MARKDOWN_CODEBK": "string"
+    }
+}
diff --git a/Source/NimbleCommander/NimbleCommander/Resources/SyntaxHighlighting/XML.json b/Source/NimbleCommander/NimbleCommander/Resources/SyntaxHighlighting/XML.json
new file mode 100644
index 000000000..6176fb7f3
--- /dev/null
+++ b/Source/NimbleCommander/NimbleCommander/Resources/SyntaxHighlighting/XML.json
@@ -0,0 +1,35 @@
+{
+    "lexer": "xml",
+    "wordlists": [],
+    "properties": {
+    },
+    "mapping": {
+        "SCE_H_DEFAULT": "default",
+        "SCE_H_TAG": "keyword",
+        "SCE_H_TAGUNKNOWN": "comment",
+        "SCE_H_ATTRIBUTE": "identifier",
+        "SCE_H_ATTRIBUTEUNKNOWN": "comment",
+        "SCE_H_NUMBER": "number",
+        "SCE_H_DOUBLESTRING": "string",
+        "SCE_H_SINGLESTRING": "string",
+        "SCE_H_OTHER": "operator",
+        "SCE_H_COMMENT": "comment",
+        "SCE_H_ENTITY": "identifier",
+        "SCE_H_TAGEND": "default",
+        "SCE_H_XMLSTART": "comment",
+        "SCE_H_XMLEND": "comment",
+        "SCE_H_CDATA": "string",
+        "SCE_H_QUESTION": "preprocessor",
+        "SCE_H_VALUE": "default",
+        "SCE_H_SGML_DEFAULT": "default",
+        "SCE_H_SGML_COMMAND": "preprocessor",
+        "SCE_H_SGML_1ST_PARAM": "preprocessor",
+        "SCE_H_SGML_DOUBLESTRING": "string",
+        "SCE_H_SGML_SIMPLESTRING": "string",
+        "SCE_H_SGML_ERROR": "comment",
+        "SCE_H_SGML_SPECIAL": "identifier",
+        "SCE_H_SGML_ENTITY": "identifier",
+        "SCE_H_SGML_COMMENT": "comment",
+        "SCE_H_SGML_BLOCK_DEFAULT": "default"
+    }
+}
diff --git a/Source/Viewer/include/Viewer/Highlighting/Document.h b/Source/Viewer/include/Viewer/Highlighting/Document.h
index 9f45f93a3..871a114c2 100644
--- a/Source/Viewer/include/Viewer/Highlighting/Document.h
+++ b/Source/Viewer/include/Viewer/Highlighting/Document.h
@@ -72,6 +72,7 @@ class Document final : public Scintilla::IDocument
     std::string_view m_Text;
     std::vector<uint32_t> m_Lines;
     std::vector<int> m_LineStates;
+    std::vector<int> m_LineLevels;
     std::vector<char> m_Styles;
     Sci_Position m_StylingPosition = 0;
 };
diff --git a/Source/Viewer/source/Highlighting/Document.cpp b/Source/Viewer/source/Highlighting/Document.cpp
index b9d2e3ccd..9f2b09e9b 100644
--- a/Source/Viewer/source/Highlighting/Document.cpp
+++ b/Source/Viewer/source/Highlighting/Document.cpp
@@ -9,6 +9,7 @@ namespace nc::viewer::hl {
 
 static constexpr char g_CR = '\x0D';
 static constexpr char g_LF = '\x0A';
+static constexpr int g_BaseLevel = 0x400;
 
 static constinit std::array<uint8_t, 256> g_UTF8Lengths = []() {
     std::array<uint8_t, 256> lengths = {};
@@ -90,6 +91,7 @@ Document::Document(const std::string_view _text) : m_Text(_text), m_Styles(_text
     }
 
     m_LineStates.resize(m_Lines.size() + 1);
+    m_LineLevels.resize(m_Lines.size(), g_BaseLevel);
 }
 
 Document::~Document() = default;
@@ -109,7 +111,7 @@ bool Document::IsDBCSLeadByte(char) const noexcept
     return false;
 }
 
-char Document::StyleAt(Sci_Position _position) const noexcept
+char Document::StyleAt(const Sci_Position _position) const noexcept
 {
     if( _position < 0 || _position >= static_cast<long>(m_Text.length()) ) {
         return 0;
@@ -117,24 +119,26 @@ char Document::StyleAt(Sci_Position _position) const noexcept
     return m_Styles[_position];
 }
 
-int Document::GetLevel(Sci_Position /*_line*/) const noexcept
+int Document::GetLevel(const Sci_Position _line) const noexcept
 {
-    abort();
-    return 0;
+    return _line >= 0 && static_cast<size_t>(_line) < m_LineLevels.size() ? m_LineLevels[_line] : g_BaseLevel;
 }
 
-int Document::SetLevel(Sci_Position /*_line*/, int /*_level*/) noexcept
+int Document::SetLevel(const Sci_Position _line, const int _level) noexcept
 {
-    abort();
-    return 0;
+    if( _line >= 0 && static_cast<size_t>(_line) < m_LineLevels.size() ) {
+        m_LineLevels[_line] = _level;
+        return _level;
+    }
+    return g_BaseLevel;
 }
 
-int Document::GetLineState(Sci_Position _line) const noexcept
+int Document::GetLineState(const Sci_Position _line) const noexcept
 {
     return m_LineStates.at(_line);
 }
 
-int Document::SetLineState(Sci_Position _line, int _state) noexcept
+int Document::SetLineState(const Sci_Position _line, const int _state) noexcept
 {
     return m_LineStates.at(_line) = _state;
 }
@@ -145,9 +149,9 @@ int Document::GetLineIndentation(Sci_Position /*_line*/) noexcept
     return 0;
 }
 
-Sci_Position Document::GetRelativePosition(Sci_Position _position, Sci_Position _offset) const noexcept
+Sci_Position Document::GetRelativePosition(const Sci_Position _position, const Sci_Position _offset) const noexcept
 {
-    return _position + _offset;
+    return _position + _offset; // TODO: is _offset in bytes or in code units?
 }
 
 int Document::GetCharacterAndWidth(Sci_Position _position, Sci_Position *_width) const noexcept