diff --git a/CMakeLists.txt b/CMakeLists.txt
index dd946ae..584faa4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -35,6 +35,12 @@ add_executable(ReclassX
     src/pluginmanager.h
     src/typeselectorpopup.h
     src/typeselectorpopup.cpp
+    src/themes/theme.h
+    src/themes/theme.cpp
+    src/themes/thememanager.h
+    src/themes/thememanager.cpp
+    src/themes/themeeditor.h
+    src/themes/themeeditor.cpp
 )
 
 target_include_directories(ReclassX PRIVATE src)
@@ -112,7 +118,8 @@ if(BUILD_TESTING)
     target_link_libraries(test_compose PRIVATE Qt6::Core Qt6::Test)
     add_test(NAME test_compose COMMAND test_compose)
 
-    add_executable(test_editor tests/test_editor.cpp src/editor.cpp src/compose.cpp src/format.cpp src/providerregistry.cpp)
+    add_executable(test_editor tests/test_editor.cpp src/editor.cpp src/compose.cpp src/format.cpp src/providerregistry.cpp
+        src/themes/theme.cpp src/themes/thememanager.cpp)
     target_include_directories(test_editor PRIVATE src)
     target_link_libraries(test_editor PRIVATE
         Qt6::Widgets Qt6::PrintSupport Qt6::Test
@@ -140,7 +147,8 @@ if(BUILD_TESTING)
     add_executable(test_controller tests/test_controller.cpp
         src/editor.cpp src/compose.cpp src/format.cpp src/controller.cpp
         src/processpicker.cpp src/processpicker.ui src/providerregistry.cpp
-        src/typeselectorpopup.cpp)
+        src/typeselectorpopup.cpp
+        src/themes/theme.cpp src/themes/thememanager.cpp)
     target_include_directories(test_controller PRIVATE src)
     target_link_libraries(test_controller PRIVATE
         Qt6::Widgets Qt6::PrintSupport Qt6::Concurrent Qt6::Test
@@ -153,7 +161,8 @@ if(BUILD_TESTING)
     add_executable(test_validation tests/test_validation.cpp
         src/editor.cpp src/compose.cpp src/format.cpp src/controller.cpp
         src/processpicker.cpp src/processpicker.ui src/providerregistry.cpp
-        src/typeselectorpopup.cpp)
+        src/typeselectorpopup.cpp
+        src/themes/theme.cpp src/themes/thememanager.cpp)
     target_include_directories(test_validation PRIVATE src)
     target_link_libraries(test_validation PRIVATE
         Qt6::Widgets Qt6::PrintSupport Qt6::Concurrent Qt6::Test
@@ -172,7 +181,8 @@ if(BUILD_TESTING)
     add_executable(test_context_menu tests/test_context_menu.cpp
         src/editor.cpp src/compose.cpp src/format.cpp src/controller.cpp
         src/processpicker.cpp src/processpicker.ui src/providerregistry.cpp
-        src/typeselectorpopup.cpp)
+        src/typeselectorpopup.cpp
+        src/themes/theme.cpp src/themes/thememanager.cpp)
     target_include_directories(test_context_menu PRIVATE src)
     target_link_libraries(test_context_menu PRIVATE
         Qt6::Widgets Qt6::PrintSupport Qt6::Concurrent Qt6::Test
@@ -193,7 +203,8 @@ if(BUILD_TESTING)
     add_executable(test_new_features tests/test_new_features.cpp
         src/generator.cpp src/compose.cpp src/format.cpp src/controller.cpp
         src/editor.cpp src/processpicker.cpp src/processpicker.ui src/providerregistry.cpp
-        src/typeselectorpopup.cpp)
+        src/typeselectorpopup.cpp
+        src/themes/theme.cpp src/themes/thememanager.cpp)
     target_include_directories(test_new_features PRIVATE src)
     target_link_libraries(test_new_features PRIVATE
         Qt6::Widgets Qt6::PrintSupport Qt6::Concurrent Qt6::Test
@@ -206,11 +217,18 @@ if(BUILD_TESTING)
     add_executable(test_type_selector tests/test_type_selector.cpp
         src/editor.cpp src/compose.cpp src/format.cpp src/controller.cpp
         src/processpicker.cpp src/processpicker.ui src/providerregistry.cpp
-        src/typeselectorpopup.cpp)
+        src/typeselectorpopup.cpp
+        src/themes/theme.cpp src/themes/thememanager.cpp)
     target_include_directories(test_type_selector PRIVATE src)
     target_link_libraries(test_type_selector PRIVATE
         Qt6::Widgets Qt6::PrintSupport Qt6::Concurrent Qt6::Test
         QScintilla::QScintilla dbghelp psapi)
     add_test(NAME test_type_selector COMMAND test_type_selector)
+
+    add_executable(test_theme tests/test_theme.cpp
+        src/themes/theme.cpp src/themes/thememanager.cpp)
+    target_include_directories(test_theme PRIVATE src)
+    target_link_libraries(test_theme PRIVATE Qt6::Widgets Qt6::Test)
+    add_test(NAME test_theme COMMAND test_theme)
 endif()
 add_subdirectory(plugins/ProcessMemory)
diff --git a/src/editor.cpp b/src/editor.cpp
index 3bf51c6..caff396 100644
--- a/src/editor.cpp
+++ b/src/editor.cpp
@@ -14,15 +14,10 @@
 #include <QCursor>
 #include <QMenu>
 #include <QApplication>
+#include "themes/thememanager.h"
 
 namespace rcx {
 
-// ── Theme constants ──
-static const QColor kBgText("#1e1e1e");
-static const QColor kBgMargin("#1e1e1e");  // matches regular editor background
-static const QColor kFgMargin("#858585");
-static const QColor kFgMarginDim("#505050");
-
 static constexpr int IND_EDITABLE   = 8;
 static constexpr int IND_HEX_DIM    = 9;
 static constexpr int IND_BASE_ADDR  = 10;  // Default text color override for command row address
@@ -54,6 +49,10 @@ RcxEditor::RcxEditor(QWidget* parent) : QWidget(parent) {
     setupMarkers();
     allocateMarginStyles();
 
+    applyTheme(ThemeManager::instance().current());
+    connect(&ThemeManager::instance(), &ThemeManager::themeChanged,
+            this, &RcxEditor::applyTheme);
+
     m_sci->installEventFilter(this);
     m_sci->viewport()->installEventFilter(this);
     m_sci->viewport()->setMouseTracking(true);
@@ -122,15 +121,9 @@ void RcxEditor::setupScintilla() {
     // Arrow cursor by default — not the I-beam (this is a structured viewer, not a text editor)
     m_sci->viewport()->setCursor(Qt::ArrowCursor);
 
-    m_sci->setPaper(kBgText);
-    m_sci->setColor(QColor("#d4d4d4"));
-
     m_sci->setTabWidth(2);
     m_sci->setIndentationsUseTabs(false);
 
-    // Caret color for dark theme
-    m_sci->setCaretForegroundColor(QColor("#d4d4d4"));
-
     // Line spacing for readability
     m_sci->SendScintilla(QsciScintillaBase::SCI_SETEXTRAASCENT, (long)2);
     m_sci->SendScintilla(QsciScintillaBase::SCI_SETEXTRADESCENT, (long)2);
@@ -147,51 +140,37 @@ void RcxEditor::setupScintilla() {
     m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETSTYLE,
                          IND_EDITABLE, 5 /*INDIC_HIDDEN*/);
 
-    // Hex/Padding node dim indicator — overrides text color to gray
+    // Hex/Padding node dim indicator — overrides text color
     m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETSTYLE,
                          IND_HEX_DIM, 17 /*INDIC_TEXTFORE*/);
-    m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETFORE,
-                         IND_HEX_DIM, QColor("#505050"));
 
-    // Base address indicator — default text color to override lexer green on command row
+    // Base address indicator — text color override on command row
     m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETSTYLE,
                          IND_BASE_ADDR, 17 /*INDIC_TEXTFORE*/);
-    m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETFORE,
-                         IND_BASE_ADDR, QColor("#d4d4d4"));
 
-    // Hover span indicator — muted teal text (distinct from blue keywords)
+    // Hover span indicator — link-like text
     m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETSTYLE,
                          IND_HOVER_SPAN, 17 /*INDIC_TEXTFORE*/);
-    m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETFORE,
-                         IND_HOVER_SPAN, QColor("#E6B450"));
 
-    // Command-row pill background (shadcn-ish chip)
+    // Command-row pill background
     m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETSTYLE,
                          IND_CMD_PILL, 8 /*INDIC_STRAIGHTBOX*/);
-    m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETFORE,
-                         IND_CMD_PILL, QColor("#2a2a2a"));
     m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETALPHA,
                          IND_CMD_PILL, (long)100);
     m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETUNDER,
                          IND_CMD_PILL, (long)1);
 
-    // Data-changed indicator — muted green text (derived from number green #b5cea8)
+    // Data-changed indicator
     m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETSTYLE,
                          IND_DATA_CHANGED, 17 /*INDIC_TEXTFORE*/);
-    m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETFORE,
-                         IND_DATA_CHANGED, QColor("#8fbc7a"));
 
-    // Root class name — teal (VS Code type color)
+    // Root class name — type color
     m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETSTYLE,
                          IND_CLASS_NAME, 17 /*INDIC_TEXTFORE*/);
-    m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETFORE,
-                         IND_CLASS_NAME, QColor("#4EC9B0"));
 
     // Green text for hint/comment annotations
     m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETSTYLE,
                          IND_HINT_GREEN, 17 /*INDIC_TEXTFORE*/);
-    m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETFORE,
-                         IND_HINT_GREEN, QColor("#5a8248"));
 
 }
 
@@ -199,29 +178,8 @@ void RcxEditor::setupLexer() {
     m_lexer = new QsciLexerCPP(m_sci);
     QFont font = editorFont();
     m_lexer->setFont(font);
-
-    // Dark theme colors
-    m_lexer->setColor(QColor("#569cd6"), QsciLexerCPP::Keyword);
-    m_lexer->setColor(QColor("#569cd6"), QsciLexerCPP::KeywordSet2);
-    m_lexer->setColor(QColor("#b5cea8"), QsciLexerCPP::Number);
-    m_lexer->setColor(QColor("#ce9178"), QsciLexerCPP::DoubleQuotedString);
-    m_lexer->setColor(QColor("#ce9178"), QsciLexerCPP::SingleQuotedString);
-    m_lexer->setColor(QColor("#6a9955"), QsciLexerCPP::Comment);
-    m_lexer->setColor(QColor("#6a9955"), QsciLexerCPP::CommentLine);
-    m_lexer->setColor(QColor("#6a9955"), QsciLexerCPP::CommentDoc);
-    m_lexer->setColor(QColor("#d4d4d4"), QsciLexerCPP::Default);
-    m_lexer->setColor(QColor("#d4d4d4"), QsciLexerCPP::Identifier);
-    m_lexer->setColor(QColor("#c586c0"), QsciLexerCPP::PreProcessor);
-    m_lexer->setColor(QColor("#d4d4d4"), QsciLexerCPP::Operator);
-
-    // Dark background for all styles
-    for (int i = 0; i <= 127; i++) {
-        m_lexer->setPaper(kBgText, i);
+    for (int i = 0; i <= 127; i++)
         m_lexer->setFont(font, i);
-    }
-
-    // Custom / user-defined types → teal (VS Code #4EC9B0)
-    m_lexer->setColor(QColor("#4EC9B0"), QsciLexerCPP::GlobalClass);
 
     m_sci->setLexer(m_lexer);
     m_sci->setBraceMatching(QsciScintilla::NoBraceMatch);  // Disable - this is a structured viewer
@@ -245,8 +203,6 @@ void RcxEditor::setupMargins() {
     // Margin 0: Offset text
     m_sci->setMarginType(0, QsciScintilla::TextMarginRightJustified);
     m_sci->setMarginWidth(0, "  00000000  ");  // default 8-digit; resized dynamically in applyDocument()
-    m_sci->setMarginsBackgroundColor(kBgMargin);
-    m_sci->setMarginsForegroundColor(kFgMarginDim);
     m_sci->setMarginSensitivity(0, true);
 
     // Margin 1: hidden (fold chevrons moved to text column)
@@ -256,7 +212,6 @@ void RcxEditor::setupMargins() {
 void RcxEditor::setupFolding() {
     // Hide fold margin (fold indicators are text-based now)
     m_sci->setMarginWidth(2, 0);
-    m_sci->setFoldMarginColors(kBgMargin, kBgMargin);
 
     // Fold indicators are now text in the line content (kFoldCol prefix),
     // so no Scintilla markers needed for fold state.
@@ -281,37 +236,26 @@ void RcxEditor::setupMarkers() {
     // M_PAD (1): padding line (metadata only, no visual)
     m_sci->markerDefine(QsciScintilla::Invisible, M_PAD);
 
-    // M_PTR0 (2): right triangle (red)
+    // M_PTR0 (2): right triangle
     m_sci->markerDefine(QsciScintilla::RightTriangle, M_PTR0);
-    m_sci->setMarkerBackgroundColor(QColor("#f44747"), M_PTR0);
-    m_sci->setMarkerForegroundColor(QColor("#f44747"), M_PTR0);
 
-    // M_CYCLE (3): arrows (orange)
+    // M_CYCLE (3): arrows
     m_sci->markerDefine(QsciScintilla::ThreeRightArrows, M_CYCLE);
-    m_sci->setMarkerBackgroundColor(QColor("#e5a00d"), M_CYCLE);
-    m_sci->setMarkerForegroundColor(QColor("#e5a00d"), M_CYCLE);
 
-    // M_ERR (4): background (dark red - brightened for visibility)
+    // M_ERR (4): background
     m_sci->markerDefine(QsciScintilla::Background, M_ERR);
-    m_sci->setMarkerBackgroundColor(QColor("#7a2e2e"), M_ERR);
-    m_sci->setMarkerForegroundColor(QColor("#ffffff"), M_ERR);
 
-    // M_STRUCT_BG (5): struct header/footer (matches regular bg, may remove later)
+    // M_STRUCT_BG (5): struct header/footer
     m_sci->markerDefine(QsciScintilla::Background, M_STRUCT_BG);
-    m_sci->setMarkerBackgroundColor(QColor("#1e1e1e"), M_STRUCT_BG);
-    m_sci->setMarkerForegroundColor(QColor("#d4d4d4"), M_STRUCT_BG);
 
     // M_HOVER (6): full-row hover highlight
     m_sci->markerDefine(QsciScintilla::Background, M_HOVER);
-    m_sci->setMarkerBackgroundColor(QColor(43, 43, 43), M_HOVER);
 
-    // M_SELECTED (7): full-row selection highlight (higher = wins over hover)
+    // M_SELECTED (7): full-row selection highlight
     m_sci->markerDefine(QsciScintilla::Background, M_SELECTED);
-    m_sci->setMarkerBackgroundColor(QColor(35, 35, 35), M_SELECTED);
 
     // M_CMD_ROW (8): distinct background for CommandRow bar
     m_sci->markerDefine(QsciScintilla::Background, M_CMD_ROW);
-    m_sci->setMarkerBackgroundColor(QColor("#1e1e1e"), M_CMD_ROW);
 }
 
 void RcxEditor::allocateMarginStyles() {
@@ -322,21 +266,87 @@ void RcxEditor::allocateMarginStyles() {
     m_marginStyleBase = (int)base;
     m_sci->SendScintilla(QsciScintillaBase::SCI_MARGINSETSTYLEOFFSET, base);
 
-    const long bgrMargin = 0x1e1e1e; // BGR for #1e1e1e (matches editor bg)
     QByteArray fontName = editorFont().family().toUtf8();
     int fontSize = editorFont().pointSize();
 
-    // Margin styles (dim gray text)
     for (int s = MSTYLE_NORMAL; s <= MSTYLE_CONT; s++) {
         unsigned long abs = (unsigned long)(base + s);
-        m_sci->SendScintilla(QsciScintillaBase::SCI_STYLESETFORE, abs, (long)0x505050);
-        m_sci->SendScintilla(QsciScintillaBase::SCI_STYLESETBACK, abs, bgrMargin);
         m_sci->SendScintilla(QsciScintillaBase::SCI_STYLESETFONT,
                              (uintptr_t)abs, fontName.constData());
         m_sci->SendScintilla(QsciScintillaBase::SCI_STYLESETSIZE, abs, (long)fontSize);
     }
 }
 
+void RcxEditor::applyTheme(const Theme& theme) {
+    // Paper and text
+    m_sci->setPaper(theme.background);
+    m_sci->setColor(theme.text);
+    m_sci->setCaretForegroundColor(theme.text);
+
+    // Indicator colors
+    m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETFORE,
+                         IND_HEX_DIM, theme.textFaint);
+    m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETFORE,
+                         IND_BASE_ADDR, theme.text);
+    m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETFORE,
+                         IND_HOVER_SPAN, theme.indHoverSpan);
+    m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETFORE,
+                         IND_CMD_PILL, theme.indCmdPill);
+    m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETFORE,
+                         IND_DATA_CHANGED, theme.indDataChanged);
+    m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETFORE,
+                         IND_CLASS_NAME, theme.syntaxType);
+    m_sci->SendScintilla(QsciScintillaBase::SCI_INDICSETFORE,
+                         IND_HINT_GREEN, theme.indHintGreen);
+
+    // Lexer colors
+    m_lexer->setColor(theme.syntaxKeyword, QsciLexerCPP::Keyword);
+    m_lexer->setColor(theme.syntaxKeyword, QsciLexerCPP::KeywordSet2);
+    m_lexer->setColor(theme.syntaxNumber, QsciLexerCPP::Number);
+    m_lexer->setColor(theme.syntaxString, QsciLexerCPP::DoubleQuotedString);
+    m_lexer->setColor(theme.syntaxString, QsciLexerCPP::SingleQuotedString);
+    m_lexer->setColor(theme.syntaxComment, QsciLexerCPP::Comment);
+    m_lexer->setColor(theme.syntaxComment, QsciLexerCPP::CommentLine);
+    m_lexer->setColor(theme.syntaxComment, QsciLexerCPP::CommentDoc);
+    m_lexer->setColor(theme.text, QsciLexerCPP::Default);
+    m_lexer->setColor(theme.text, QsciLexerCPP::Identifier);
+    m_lexer->setColor(theme.syntaxPreproc, QsciLexerCPP::PreProcessor);
+    m_lexer->setColor(theme.text, QsciLexerCPP::Operator);
+    m_lexer->setColor(theme.syntaxType, QsciLexerCPP::GlobalClass);
+    for (int i = 0; i <= 127; i++)
+        m_lexer->setPaper(theme.background, i);
+
+    // Margins
+    m_sci->setMarginsBackgroundColor(theme.background);
+    m_sci->setMarginsForegroundColor(theme.textFaint);
+    m_sci->setFoldMarginColors(theme.background, theme.background);
+
+    // Markers
+    m_sci->setMarkerBackgroundColor(theme.markerPtr, M_PTR0);
+    m_sci->setMarkerForegroundColor(theme.markerPtr, M_PTR0);
+    m_sci->setMarkerBackgroundColor(theme.markerCycle, M_CYCLE);
+    m_sci->setMarkerForegroundColor(theme.markerCycle, M_CYCLE);
+    m_sci->setMarkerBackgroundColor(theme.markerError, M_ERR);
+    m_sci->setMarkerForegroundColor(QColor("#ffffff"), M_ERR);
+    m_sci->setMarkerBackgroundColor(theme.background, M_STRUCT_BG);
+    m_sci->setMarkerForegroundColor(theme.text, M_STRUCT_BG);
+    m_sci->setMarkerBackgroundColor(theme.hover, M_HOVER);
+    m_sci->setMarkerBackgroundColor(theme.selected, M_SELECTED);
+    m_sci->setMarkerBackgroundColor(theme.background, M_CMD_ROW);
+
+    // Margin extended styles
+    if (m_marginStyleBase >= 0) {
+        long base = m_marginStyleBase;
+        for (int s = 0; s <= 1; s++) {
+            unsigned long abs = (unsigned long)(base + s);
+            m_sci->SendScintilla(QsciScintillaBase::SCI_STYLESETFORE,
+                                 abs, theme.textFaint);
+            m_sci->SendScintilla(QsciScintillaBase::SCI_STYLESETBACK,
+                                 abs, theme.background);
+        }
+    }
+}
+
 void RcxEditor::applyDocument(const ComposeResult& result) {
     // Silently deactivate inline edit (no signal — refresh is already happening)
     if (m_editState.active)
@@ -1561,7 +1571,7 @@ bool RcxEditor::beginInlineEdit(EditTarget target, int line) {
     m_sci->SendScintilla(QsciScintillaBase::SCI_SETSELFORE, (long)0, (long)0);
     if (!isPicker)
         m_sci->SendScintilla(QsciScintillaBase::SCI_SETSELBACK, (long)1,
-                             QColor("#264f78"));
+                             ThemeManager::instance().current().selection);
 
     // Use correct UTF-8 position conversion (not lineStart + col!)
     m_editState.posStart = posFromCol(m_sci, line, norm.start);
diff --git a/src/editor.h b/src/editor.h
index f9cb5ed..5312308 100644
--- a/src/editor.h
+++ b/src/editor.h
@@ -1,5 +1,6 @@
 #pragma once
 #include "core.h"
+#include "themes/theme.h"
 #include <QWidget>
 #include <QSet>
 #include <QPoint>
@@ -47,6 +48,7 @@ public:
     void setCommandRowText(const QString& line);
     void setEditorFont(const QString& fontName);
     static void setGlobalFontName(const QString& fontName);
+    void applyTheme(const Theme& theme);
 
     // Custom type names (struct types from the tree) shown in type picker + lexer GlobalClass coloring
     QString textWithMargins() const;
diff --git a/src/main.cpp b/src/main.cpp
index eaa9403..00cdd02 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -41,6 +41,8 @@
 #include <Qsci/qscilexercpp.h>
 #include <QProxyStyle>
 #include <QDesktopServices>
+#include "themes/thememanager.h"
+#include "themes/themeeditor.h"
 
 #ifdef _WIN32
 #include <windows.h>
@@ -128,6 +130,44 @@ public:
     }
 };
 
+static void applyGlobalTheme(const rcx::Theme& theme) {
+    QPalette pal;
+    pal.setColor(QPalette::Window,          theme.background);
+    pal.setColor(QPalette::WindowText,      theme.text);
+    pal.setColor(QPalette::Base,            theme.backgroundAlt);
+    pal.setColor(QPalette::AlternateBase,   theme.surface);
+    pal.setColor(QPalette::Text,            theme.text);
+    pal.setColor(QPalette::Button,          theme.button);
+    pal.setColor(QPalette::ButtonText,      theme.text);
+    pal.setColor(QPalette::Highlight,       theme.hover);
+    pal.setColor(QPalette::HighlightedText, theme.text);
+    pal.setColor(QPalette::ToolTipBase,     theme.backgroundAlt);
+    pal.setColor(QPalette::ToolTipText,     theme.text);
+    pal.setColor(QPalette::Mid,             theme.border);
+    pal.setColor(QPalette::Dark,            theme.background);
+    pal.setColor(QPalette::Light,           theme.textFaint);
+    qApp->setPalette(pal);
+
+    qApp->setStyleSheet(QStringLiteral(
+        "QMenu {"
+        "  background-color: %1;"
+        "  color: %2;"
+        "  border: 1px solid %3;"
+        "  padding: 4px 6px;"
+        "}"
+        "QMenu::item { padding: 4px 24px; }"
+        "QMenu::item:selected { background-color: %4; }"
+        "QMenu::separator { height: 1px; background: %3; margin: 4px 8px; }"
+        "QMenu::item:disabled { color: %5; }"
+        "QToolTip {"
+        "  background-color: %1;"
+        "  color: %2;"
+        "  border: 1px solid %3;"
+        "}")
+        .arg(theme.backgroundAlt.name(), theme.text.name(), theme.border.name(),
+             theme.hover.name(), theme.textMuted.name()));
+}
+
 namespace rcx {
 
 class MainWindow : public QMainWindow {
@@ -158,6 +198,7 @@ private slots:
     void setEditorFont(const QString& fontName);
     void exportCpp();
     void showTypeAliasesDialog();
+    void editTheme();
 
 public:
     // Project Lifecycle API
@@ -208,6 +249,7 @@ private:
     void setupRenderedSci(QsciScintilla* sci);
 
     SplitPane createSplitPane(TabState& tab);
+    void applyTheme(const Theme& theme);
     void applyTabWidgetStyle(QTabWidget* tw);
     SplitPane* findPaneByTabWidget(QTabWidget* tw);
     SplitPane* findActiveSplitPane();
@@ -229,22 +271,17 @@ MainWindow::MainWindow(QWidget* parent) : QMainWindow(parent) {
     m_mdiArea->setViewMode(QMdiArea::TabbedView);
     m_mdiArea->setTabsClosable(true);
     m_mdiArea->setTabsMovable(true);
-    m_mdiArea->setStyleSheet(QStringLiteral(
-        "QTabBar::tab {"
-        "  background: #1e1e1e;"
-        "  color: #585858;"
-        "  padding: 6px 16px;"
-        "  border: none;"
-        "}"
-        "QTabBar::tab:selected {"
-        "  color: #d4d4d4;"
-        "  background: #252526;"
-        "}"
-        "QTabBar::tab:hover {"
-        "  color: #d4d4d4;"
-        "  background: #2b2b2b;"
-        "}"
-    ));
+    {
+        const auto& t = ThemeManager::instance().current();
+        m_mdiArea->setStyleSheet(QStringLiteral(
+            "QTabBar::tab {"
+            "  background: %1; color: %2; padding: 6px 16px; border: none;"
+            "}"
+            "QTabBar::tab:selected { color: %3; background: %4; }"
+            "QTabBar::tab:hover { color: %3; background: %5; }")
+            .arg(t.background.name(), t.textMuted.name(), t.text.name(),
+                 t.backgroundAlt.name(), t.hover.name()));
+    }
     setCentralWidget(m_mdiArea);
 
     createWorkspaceDock();
@@ -257,6 +294,9 @@ MainWindow::MainWindow(QWidget* parent) : QMainWindow(parent) {
         menuBar()->setStyle(new MenuBarStyle(menuBar()->style()));
     }
 
+    connect(&ThemeManager::instance(), &ThemeManager::themeChanged,
+            this, &MainWindow::applyTheme);
+
     // Load plugins
     m_pluginManager.LoadPlugins();
 
@@ -327,6 +367,24 @@ void MainWindow::createMenus() {
     connect(actConsolas, &QAction::triggered, this, [this]() { setEditorFont("Consolas"); });
     connect(actJetBrains, &QAction::triggered, this, [this]() { setEditorFont("JetBrains Mono"); });
 
+    // Theme submenu
+    auto* themeMenu = view->addMenu("&Theme");
+    auto* themeGroup = new QActionGroup(this);
+    themeGroup->setExclusive(true);
+    auto& tm = ThemeManager::instance();
+    auto allThemes = tm.themes();
+    for (int i = 0; i < allThemes.size(); i++) {
+        auto* act = themeMenu->addAction(allThemes[i].name);
+        act->setCheckable(true);
+        act->setActionGroup(themeGroup);
+        if (i == tm.currentIndex()) act->setChecked(true);
+        connect(act, &QAction::triggered, this, [i]() {
+            ThemeManager::instance().setCurrent(i);
+        });
+    }
+    themeMenu->addSeparator();
+    themeMenu->addAction("Edit Theme...", this, &MainWindow::editTheme);
+
     view->addSeparator();
     view->addAction(m_workspaceDock->toggleViewAction());
 
@@ -351,7 +409,12 @@ void MainWindow::createStatusBar() {
     m_statusLabel = new QLabel("Ready");
     m_statusLabel->setContentsMargins(10, 0, 0, 0);
     statusBar()->addWidget(m_statusLabel, 1);
-    statusBar()->setStyleSheet("QStatusBar { background: #252526; color: #858585; }");
+    {
+        const auto& t = ThemeManager::instance().current();
+        statusBar()->setStyleSheet(QStringLiteral(
+            "QStatusBar { background: %1; color: %2; }")
+            .arg(t.backgroundAlt.name(), t.textDim.name()));
+    }
 
     QSettings settings("ReclassX", "ReclassX");
     QString fontName = settings.value("font", "JetBrains Mono").toString();
@@ -366,23 +429,16 @@ void MainWindow::applyTabWidgetStyle(QTabWidget* tw) {
     QFont tabFont(fontName, 12);
     tabFont.setFixedPitch(true);
     tw->tabBar()->setFont(tabFont);
+    const auto& t = ThemeManager::instance().current();
     tw->setStyleSheet(QStringLiteral(
         "QTabWidget::pane { border: none; }"
         "QTabBar::tab {"
-        "  background: #1e1e1e;"
-        "  color: #585858;"
-        "  padding: 4px 12px;"
-        "  border: none;"
-        "  min-width: 60px;"
+        "  background: %1; color: %2; padding: 4px 12px; border: none; min-width: 60px;"
         "}"
-        "QTabBar::tab:selected {"
-        "  color: #d4d4d4;"
-        "}"
-        "QTabBar::tab:hover {"
-        "  color: #d4d4d4;"
-        "  background: #2b2b2b;"
-        "}"
-    ));
+        "QTabBar::tab:selected { color: %3; }"
+        "QTabBar::tab:hover { color: %3; background: %4; }")
+        .arg(t.background.name(), t.textMuted.name(),
+             t.text.name(), t.hover.name()));
     tw->tabBar()->setExpanding(false);
 }
 
@@ -754,28 +810,74 @@ void MainWindow::about() {
     lay->setSpacing(12);
 
     auto* buildLabel = new QLabel(
-        QStringLiteral("<span style='color:#858585;font-size:11px;'>"
-                       "Build&ensp;" __DATE__ "&ensp;" __TIME__ "</span>"));
+        QStringLiteral("<span style='color:%1;font-size:11px;'>"
+                       "Build&ensp;" __DATE__ "&ensp;" __TIME__ "</span>")
+            .arg(ThemeManager::instance().current().textDim.name()));
     buildLabel->setAlignment(Qt::AlignCenter);
     lay->addWidget(buildLabel);
 
     auto* ghBtn = new QPushButton("GitHub");
     ghBtn->setCursor(Qt::PointingHandCursor);
-    ghBtn->setStyleSheet(
-        "QPushButton {"
-        "  background: #2a2a2a; color: #d4d4d4; border: 1px solid #3f3f3f;"
-        "  border-radius: 4px; padding: 5px 16px; font-size: 12px;"
-        "}"
-        "QPushButton:hover { background: #333333; border-color: #505050; }");
+    {
+        const auto& t = ThemeManager::instance().current();
+        ghBtn->setStyleSheet(QStringLiteral(
+            "QPushButton {"
+            "  background: %1; color: %2; border: 1px solid %3;"
+            "  border-radius: 4px; padding: 5px 16px; font-size: 12px;"
+            "}"
+            "QPushButton:hover { background: %4; border-color: %5; }")
+            .arg(t.indCmdPill.name(), t.text.name(), t.border.name(),
+                 t.button.name(), t.textFaint.name()));
+    }
     connect(ghBtn, &QPushButton::clicked, this, []() {
         QDesktopServices::openUrl(QUrl("https://github.com/IChooseYou/Reclass"));
     });
     lay->addWidget(ghBtn, 0, Qt::AlignCenter);
 
-    dlg.setStyleSheet("QDialog { background: #1e1e1e; }");
+    dlg.setStyleSheet(QStringLiteral("QDialog { background: %1; }")
+        .arg(ThemeManager::instance().current().background.name()));
     dlg.exec();
 }
 
+void MainWindow::applyTheme(const Theme& theme) {
+    applyGlobalTheme(theme);
+
+    // MDI area tabs
+    m_mdiArea->setStyleSheet(QStringLiteral(
+        "QTabBar::tab {"
+        "  background: %1; color: %2; padding: 6px 16px; border: none;"
+        "}"
+        "QTabBar::tab:selected { color: %3; background: %4; }"
+        "QTabBar::tab:hover { color: %3; background: %5; }")
+        .arg(theme.background.name(), theme.textMuted.name(), theme.text.name(),
+             theme.backgroundAlt.name(), theme.hover.name()));
+
+    // Status bar
+    statusBar()->setStyleSheet(QStringLiteral(
+        "QStatusBar { background: %1; color: %2; }")
+        .arg(theme.backgroundAlt.name(), theme.textDim.name()));
+
+    // Split pane tab widgets
+    for (auto& state : m_tabs) {
+        for (auto& pane : state.panes) {
+            if (pane.tabWidget) applyTabWidgetStyle(pane.tabWidget);
+        }
+    }
+}
+
+void MainWindow::editTheme() {
+    auto& tm = ThemeManager::instance();
+    Theme edited = tm.current();
+    ThemeEditor dlg(edited, this);
+    if (dlg.exec() == QDialog::Accepted) {
+        edited = dlg.result();
+        int idx = tm.currentIndex();
+        if (idx < tm.themes().size() && idx >= 0) {
+            tm.updateTheme(idx, edited);
+        }
+    }
+}
+
 void MainWindow::setEditorFont(const QString& fontName) {
     QSettings settings("ReclassX", "ReclassX");
     settings.setValue("font", fontName);
@@ -852,8 +954,9 @@ void MainWindow::setupRenderedSci(QsciScintilla* sci) {
     // Line number margin
     sci->setMarginType(0, QsciScintilla::NumberMargin);
     sci->setMarginWidth(0, "00000");
-    sci->setMarginsBackgroundColor(QColor("#252526"));
-    sci->setMarginsForegroundColor(QColor("#858585"));
+    const auto& theme = ThemeManager::instance().current();
+    sci->setMarginsBackgroundColor(theme.backgroundAlt);
+    sci->setMarginsForegroundColor(theme.textDim);
     sci->setMarginsFont(f);
 
     // Hide other margins
@@ -864,33 +967,33 @@ void MainWindow::setupRenderedSci(QsciScintilla* sci) {
     // because setLexer() resets caret line, selection, and paper colors.
     auto* lexer = new QsciLexerCPP(sci);
     lexer->setFont(f);
-    lexer->setColor(QColor("#569cd6"), QsciLexerCPP::Keyword);
-    lexer->setColor(QColor("#569cd6"), QsciLexerCPP::KeywordSet2);
-    lexer->setColor(QColor("#b5cea8"), QsciLexerCPP::Number);
-    lexer->setColor(QColor("#ce9178"), QsciLexerCPP::DoubleQuotedString);
-    lexer->setColor(QColor("#ce9178"), QsciLexerCPP::SingleQuotedString);
-    lexer->setColor(QColor("#6a9955"), QsciLexerCPP::Comment);
-    lexer->setColor(QColor("#6a9955"), QsciLexerCPP::CommentLine);
-    lexer->setColor(QColor("#6a9955"), QsciLexerCPP::CommentDoc);
-    lexer->setColor(QColor("#d4d4d4"), QsciLexerCPP::Default);
-    lexer->setColor(QColor("#d4d4d4"), QsciLexerCPP::Identifier);
-    lexer->setColor(QColor("#c586c0"), QsciLexerCPP::PreProcessor);
-    lexer->setColor(QColor("#d4d4d4"), QsciLexerCPP::Operator);
+    lexer->setColor(theme.syntaxKeyword, QsciLexerCPP::Keyword);
+    lexer->setColor(theme.syntaxKeyword, QsciLexerCPP::KeywordSet2);
+    lexer->setColor(theme.syntaxNumber, QsciLexerCPP::Number);
+    lexer->setColor(theme.syntaxString, QsciLexerCPP::DoubleQuotedString);
+    lexer->setColor(theme.syntaxString, QsciLexerCPP::SingleQuotedString);
+    lexer->setColor(theme.syntaxComment, QsciLexerCPP::Comment);
+    lexer->setColor(theme.syntaxComment, QsciLexerCPP::CommentLine);
+    lexer->setColor(theme.syntaxComment, QsciLexerCPP::CommentDoc);
+    lexer->setColor(theme.text, QsciLexerCPP::Default);
+    lexer->setColor(theme.text, QsciLexerCPP::Identifier);
+    lexer->setColor(theme.syntaxPreproc, QsciLexerCPP::PreProcessor);
+    lexer->setColor(theme.text, QsciLexerCPP::Operator);
     for (int i = 0; i <= 127; i++) {
-        lexer->setPaper(QColor("#1e1e1e"), i);
+        lexer->setPaper(theme.background, i);
         lexer->setFont(f, i);
     }
     sci->setLexer(lexer);
     sci->setBraceMatching(QsciScintilla::NoBraceMatch);
 
     // Colors applied AFTER setLexer() — the lexer resets these on attach
-    sci->setPaper(QColor("#1e1e1e"));
-    sci->setColor(QColor("#d4d4d4"));
-    sci->setCaretForegroundColor(QColor("#d4d4d4"));
+    sci->setPaper(theme.background);
+    sci->setColor(theme.text);
+    sci->setCaretForegroundColor(theme.text);
     sci->setCaretLineVisible(true);
-    sci->setCaretLineBackgroundColor(QColor(43, 43, 43));   // Match Reclass M_HOVER
-    sci->setSelectionBackgroundColor(QColor("#264f78"));     // Match Reclass edit selection
-    sci->setSelectionForegroundColor(QColor("#d4d4d4"));
+    sci->setCaretLineBackgroundColor(theme.hover);
+    sci->setSelectionBackgroundColor(theme.selection);
+    sci->setSelectionForegroundColor(theme.text);
 }
 
 // ── View mode / generator switching ──
@@ -1333,54 +1436,8 @@ int main(int argc, char* argv[]) {
         rcx::RcxEditor::setGlobalFontName(savedFont);
     }
 
-    // Global dark palette
-    QPalette darkPalette;
-    darkPalette.setColor(QPalette::Window,          QColor("#1e1e1e"));
-    darkPalette.setColor(QPalette::WindowText,      QColor("#d4d4d4"));
-    darkPalette.setColor(QPalette::Base,            QColor("#252526"));
-    darkPalette.setColor(QPalette::AlternateBase,   QColor("#2a2d2e"));
-    darkPalette.setColor(QPalette::Text,            QColor("#d4d4d4"));
-    darkPalette.setColor(QPalette::Button,          QColor("#333333"));
-    darkPalette.setColor(QPalette::ButtonText,      QColor("#d4d4d4"));
-    darkPalette.setColor(QPalette::Highlight,       QColor("#2b2b2b"));
-    darkPalette.setColor(QPalette::HighlightedText, QColor("#d4d4d4"));
-    darkPalette.setColor(QPalette::ToolTipBase,     QColor("#252526"));
-    darkPalette.setColor(QPalette::ToolTipText,     QColor("#d4d4d4"));
-    darkPalette.setColor(QPalette::Mid,             QColor("#3c3c3c"));
-    darkPalette.setColor(QPalette::Dark,            QColor("#1e1e1e"));
-    darkPalette.setColor(QPalette::Light,           QColor("#505050"));
-    app.setPalette(darkPalette);
-
-    // ── Global widget styling ──
-    // QMenu: grey hover, amber accent border (replaces Fusion outline artifact)
-    // QToolTip: dark theme
-    app.setStyleSheet(QStringLiteral(
-        "QMenu {"
-        "  background-color: #252526;"
-        "  color: #d4d4d4;"
-        "  border: 1px solid #3c3c3c;"
-        "  padding: 4px 6px;"
-        "}"
-        "QMenu::item {"
-        "  padding: 4px 24px;"
-        "}"
-        "QMenu::item:selected {"
-        "  background-color: #2b2b2b;"
-        "}"
-        "QMenu::separator {"
-        "  height: 1px;"
-        "  background: #3c3c3c;"
-        "  margin: 4px 8px;"
-        "}"
-        "QMenu::item:disabled {"
-        "  color: #585858;"
-        "}"
-        "QToolTip {"
-        "  background-color: #252526;"
-        "  color: #d4d4d4;"
-        "  border: 1px solid #3c3c3c;"
-        "}"
-    ));
+    // Global theme
+    applyGlobalTheme(rcx::ThemeManager::instance().current());
 
     rcx::MainWindow window;
 
diff --git a/src/themes/theme.cpp b/src/themes/theme.cpp
new file mode 100644
index 0000000..3704a14
--- /dev/null
+++ b/src/themes/theme.cpp
@@ -0,0 +1,119 @@
+#include "theme.h"
+
+namespace rcx {
+
+// ── Field table for DRY serialization ──
+
+struct ColorField { const char* key; QColor Theme::*ptr; };
+
+static const ColorField kFields[] = {
+    {"background",    &Theme::background},
+    {"backgroundAlt", &Theme::backgroundAlt},
+    {"surface",       &Theme::surface},
+    {"border",        &Theme::border},
+    {"button",        &Theme::button},
+    {"text",          &Theme::text},
+    {"textDim",       &Theme::textDim},
+    {"textMuted",     &Theme::textMuted},
+    {"textFaint",     &Theme::textFaint},
+    {"hover",         &Theme::hover},
+    {"selected",      &Theme::selected},
+    {"selection",     &Theme::selection},
+    {"syntaxKeyword", &Theme::syntaxKeyword},
+    {"syntaxNumber",  &Theme::syntaxNumber},
+    {"syntaxString",  &Theme::syntaxString},
+    {"syntaxComment", &Theme::syntaxComment},
+    {"syntaxPreproc", &Theme::syntaxPreproc},
+    {"syntaxType",    &Theme::syntaxType},
+    {"indHoverSpan",  &Theme::indHoverSpan},
+    {"indCmdPill",    &Theme::indCmdPill},
+    {"indDataChanged",&Theme::indDataChanged},
+    {"indHintGreen",  &Theme::indHintGreen},
+    {"markerPtr",     &Theme::markerPtr},
+    {"markerCycle",   &Theme::markerCycle},
+    {"markerError",   &Theme::markerError},
+};
+
+QJsonObject Theme::toJson() const {
+    QJsonObject o;
+    o["name"] = name;
+    for (const auto& f : kFields)
+        o[f.key] = (this->*f.ptr).name();
+    return o;
+}
+
+Theme Theme::fromJson(const QJsonObject& o) {
+    Theme t = reclassDark();
+    t.name = o["name"].toString(t.name);
+    for (const auto& f : kFields) {
+        if (o.contains(f.key))
+            t.*f.ptr = QColor(o[f.key].toString());
+    }
+    return t;
+}
+
+// ── Built-in themes ──
+
+Theme Theme::reclassDark() {
+    Theme t;
+    t.name          = "Reclass Dark";
+    t.background    = QColor("#1e1e1e");
+    t.backgroundAlt = QColor("#252526");
+    t.surface       = QColor("#2a2d2e");
+    t.border        = QColor("#3c3c3c");
+    t.button        = QColor("#333333");
+    t.text          = QColor("#d4d4d4");
+    t.textDim       = QColor("#858585");
+    t.textMuted     = QColor("#585858");
+    t.textFaint     = QColor("#505050");
+    t.hover         = QColor("#2b2b2b");
+    t.selected      = QColor("#232323");
+    t.selection     = QColor("#2b2b2b");
+    t.syntaxKeyword = QColor("#569cd6");
+    t.syntaxNumber  = QColor("#b5cea8");
+    t.syntaxString  = QColor("#ce9178");
+    t.syntaxComment = QColor("#6a9955");
+    t.syntaxPreproc = QColor("#c586c0");
+    t.syntaxType    = QColor("#4EC9B0");
+    t.indHoverSpan  = QColor("#E6B450");
+    t.indCmdPill    = QColor("#2a2a2a");
+    t.indDataChanged= QColor("#8fbc7a");
+    t.indHintGreen  = QColor("#5a8248");
+    t.markerPtr     = QColor("#f44747");
+    t.markerCycle   = QColor("#e5a00d");
+    t.markerError   = QColor("#7a2e2e");
+    return t;
+}
+
+Theme Theme::warm() {
+    Theme t;
+    t.name          = "Warm";
+    t.background    = QColor("#212121");
+    t.backgroundAlt = QColor("#2a2a2a");
+    t.surface       = QColor("#2a2a2a");
+    t.border        = QColor("#373737");
+    t.button        = QColor("#373737");
+    t.text          = QColor("#AAA99F");
+    t.textDim       = QColor("#7a7a6e");
+    t.textMuted     = QColor("#555550");
+    t.textFaint     = QColor("#464646");
+    t.hover         = QColor("#373737");
+    t.selected      = QColor("#2d2d2d");
+    t.selection     = QColor("#21213A");
+    t.syntaxKeyword = QColor("#AA9565");
+    t.syntaxNumber  = QColor("#AAA98C");
+    t.syntaxString  = QColor("#6B3B21");
+    t.syntaxComment = QColor("#464646");
+    t.syntaxPreproc = QColor("#AA9565");
+    t.syntaxType    = QColor("#6B959F");
+    t.indHoverSpan  = QColor("#AA9565");
+    t.indCmdPill    = QColor("#2a2a2a");
+    t.indDataChanged= QColor("#6B959F");
+    t.indHintGreen  = QColor("#464646");
+    t.markerPtr     = QColor("#6B3B21");
+    t.markerCycle   = QColor("#AA9565");
+    t.markerError   = QColor("#3C2121");
+    return t;
+}
+
+} // namespace rcx
diff --git a/src/themes/theme.h b/src/themes/theme.h
new file mode 100644
index 0000000..6eed657
--- /dev/null
+++ b/src/themes/theme.h
@@ -0,0 +1,55 @@
+#pragma once
+#include <QColor>
+#include <QString>
+#include <QJsonObject>
+
+namespace rcx {
+
+struct Theme {
+    QString name;
+
+    // ── Chrome ──
+    QColor background;      // editor bg, margin bg, window
+    QColor backgroundAlt;   // panels, tab selected, tooltips
+    QColor surface;         // alternateBase
+    QColor border;          // separators, menu borders
+    QColor button;          // button bg
+
+    // ── Text ──
+    QColor text;            // primary text, caret, identifiers
+    QColor textDim;         // margin fg, status bar
+    QColor textMuted;       // inactive tab, disabled menu
+    QColor textFaint;       // margin dim, hex dim
+
+    // ── Interactive ──
+    QColor hover;           // row hover, tab hover, menu hover
+    QColor selected;        // row selection highlight
+    QColor selection;       // text selection background
+
+    // ── Syntax ──
+    QColor syntaxKeyword;
+    QColor syntaxNumber;
+    QColor syntaxString;
+    QColor syntaxComment;
+    QColor syntaxPreproc;
+    QColor syntaxType;      // custom types / GlobalClass
+
+    // ── Indicators ──
+    QColor indHoverSpan;    // hover link text
+    QColor indCmdPill;      // command row pill bg
+    QColor indDataChanged;  // changed data values
+    QColor indHintGreen;    // comment/hint text
+
+    // ── Markers ──
+    QColor markerPtr;       // null pointer
+    QColor markerCycle;     // cycle detection
+    QColor markerError;     // error row bg
+
+    QJsonObject toJson() const;
+    static Theme fromJson(const QJsonObject& obj);
+
+    static Theme reclassDark();
+    static Theme warm();
+};
+
+} // namespace rcx
diff --git a/src/themes/themeeditor.cpp b/src/themes/themeeditor.cpp
new file mode 100644
index 0000000..3637e1e
--- /dev/null
+++ b/src/themes/themeeditor.cpp
@@ -0,0 +1,95 @@
+#include "themeeditor.h"
+#include <QFormLayout>
+#include <QDialogButtonBox>
+#include <QColorDialog>
+#include <QLineEdit>
+#include <QLabel>
+
+namespace rcx {
+
+ThemeEditor::ThemeEditor(const Theme& theme, QWidget* parent)
+    : QDialog(parent), m_theme(theme)
+{
+    setWindowTitle("Edit Theme");
+    setMinimumWidth(320);
+
+    auto* form = new QFormLayout;
+
+    // Name field
+    auto* nameEdit = new QLineEdit(m_theme.name);
+    connect(nameEdit, &QLineEdit::textChanged, this, [this](const QString& t) {
+        m_theme.name = t;
+    });
+    form->addRow("Name", nameEdit);
+
+    // Color swatches
+    struct FieldDef { const char* label; QColor Theme::*ptr; };
+    const FieldDef fields[] = {
+        {"Background",      &Theme::background},
+        {"Background Alt",  &Theme::backgroundAlt},
+        {"Surface",         &Theme::surface},
+        {"Border",          &Theme::border},
+        {"Button",          &Theme::button},
+        {"Text",            &Theme::text},
+        {"Text Dim",        &Theme::textDim},
+        {"Text Muted",      &Theme::textMuted},
+        {"Text Faint",      &Theme::textFaint},
+        {"Hover",           &Theme::hover},
+        {"Selected",        &Theme::selected},
+        {"Selection",       &Theme::selection},
+        {"Keyword",         &Theme::syntaxKeyword},
+        {"Number",          &Theme::syntaxNumber},
+        {"String",          &Theme::syntaxString},
+        {"Comment",         &Theme::syntaxComment},
+        {"Preprocessor",    &Theme::syntaxPreproc},
+        {"Type",            &Theme::syntaxType},
+        {"Hover Span",      &Theme::indHoverSpan},
+        {"Cmd Pill",        &Theme::indCmdPill},
+        {"Data Changed",    &Theme::indDataChanged},
+        {"Hint Green",      &Theme::indHintGreen},
+        {"Pointer Marker",  &Theme::markerPtr},
+        {"Cycle Marker",    &Theme::markerCycle},
+        {"Error Marker",    &Theme::markerError},
+    };
+
+    for (const auto& f : fields) {
+        auto* btn = new QPushButton;
+        btn->setFixedSize(60, 24);
+        btn->setCursor(Qt::PointingHandCursor);
+        SwatchEntry entry{f.label, f.ptr, btn};
+        m_swatches.append(entry);
+        updateSwatch(m_swatches.last());
+
+        int idx = m_swatches.size() - 1;
+        connect(btn, &QPushButton::clicked, this, [this, idx]() {
+            pickColor(m_swatches[idx]);
+        });
+        form->addRow(f.label, btn);
+    }
+
+    auto* buttons = new QDialogButtonBox(QDialogButtonBox::Ok | QDialogButtonBox::Cancel);
+    connect(buttons, &QDialogButtonBox::accepted, this, &QDialog::accept);
+    connect(buttons, &QDialogButtonBox::rejected, this, &QDialog::reject);
+
+    auto* layout = new QVBoxLayout(this);
+    layout->addLayout(form);
+    layout->addWidget(buttons);
+}
+
+void ThemeEditor::updateSwatch(SwatchEntry& entry) {
+    QColor c = m_theme.*entry.field;
+    entry.button->setStyleSheet(QStringLiteral(
+        "QPushButton { background: %1; border: 1px solid #555; border-radius: 3px; }")
+        .arg(c.name()));
+    entry.button->setToolTip(c.name());
+}
+
+void ThemeEditor::pickColor(SwatchEntry& entry) {
+    QColor c = QColorDialog::getColor(m_theme.*entry.field, this, entry.label);
+    if (c.isValid()) {
+        m_theme.*entry.field = c;
+        updateSwatch(entry);
+    }
+}
+
+} // namespace rcx
diff --git a/src/themes/themeeditor.h b/src/themes/themeeditor.h
new file mode 100644
index 0000000..98f2ca9
--- /dev/null
+++ b/src/themes/themeeditor.h
@@ -0,0 +1,29 @@
+#pragma once
+#include "theme.h"
+#include <QDialog>
+#include <QVector>
+#include <QPushButton>
+
+namespace rcx {
+
+class ThemeEditor : public QDialog {
+    Q_OBJECT
+public:
+    explicit ThemeEditor(const Theme& theme, QWidget* parent = nullptr);
+    Theme result() const { return m_theme; }
+
+private:
+    Theme m_theme;
+
+    struct SwatchEntry {
+        const char* label;
+        QColor Theme::*field;
+        QPushButton* button;
+    };
+    QVector<SwatchEntry> m_swatches;
+
+    void updateSwatch(SwatchEntry& entry);
+    void pickColor(SwatchEntry& entry);
+};
+
+} // namespace rcx
diff --git a/src/themes/thememanager.cpp b/src/themes/thememanager.cpp
new file mode 100644
index 0000000..c493eba
--- /dev/null
+++ b/src/themes/thememanager.cpp
@@ -0,0 +1,119 @@
+#include "thememanager.h"
+#include <QSettings>
+#include <QDir>
+#include <QFile>
+#include <QJsonDocument>
+#include <QStandardPaths>
+
+namespace rcx {
+
+ThemeManager& ThemeManager::instance() {
+    static ThemeManager s;
+    return s;
+}
+
+ThemeManager::ThemeManager() {
+    m_builtIn.append(Theme::reclassDark());
+    m_builtIn.append(Theme::warm());
+    loadUserThemes();
+
+    QSettings settings("ReclassX", "ReclassX");
+    QString saved = settings.value("theme", m_builtIn[0].name).toString();
+    auto all = themes();
+    for (int i = 0; i < all.size(); i++) {
+        if (all[i].name == saved) { m_currentIdx = i; break; }
+    }
+}
+
+QVector<Theme> ThemeManager::themes() const {
+    QVector<Theme> all = m_builtIn;
+    all.append(m_user);
+    return all;
+}
+
+const Theme& ThemeManager::current() const {
+    if (m_currentIdx < m_builtIn.size())
+        return m_builtIn[m_currentIdx];
+    int userIdx = m_currentIdx - m_builtIn.size();
+    if (userIdx >= 0 && userIdx < m_user.size())
+        return m_user[userIdx];
+    return m_builtIn[0];
+}
+
+void ThemeManager::setCurrent(int index) {
+    auto all = themes();
+    if (index < 0 || index >= all.size()) return;
+    m_currentIdx = index;
+    QSettings settings("ReclassX", "ReclassX");
+    settings.setValue("theme", all[index].name);
+    emit themeChanged(current());
+}
+
+void ThemeManager::addTheme(const Theme& theme) {
+    m_user.append(theme);
+    saveUserThemes();
+}
+
+void ThemeManager::updateTheme(int index, const Theme& theme) {
+    if (index < builtInCount()) {
+        // Can't overwrite built-in; save as user theme instead
+        m_user.append(theme);
+    } else {
+        int ui = index - builtInCount();
+        if (ui >= 0 && ui < m_user.size())
+            m_user[ui] = theme;
+    }
+    saveUserThemes();
+    if (index == m_currentIdx)
+        emit themeChanged(current());
+}
+
+void ThemeManager::removeTheme(int index) {
+    if (index < builtInCount()) return;
+    int ui = index - builtInCount();
+    if (ui < 0 || ui >= m_user.size()) return;
+    m_user.remove(ui);
+    if (m_currentIdx == index) {
+        m_currentIdx = 0;
+        emit themeChanged(current());
+    } else if (m_currentIdx > index) {
+        m_currentIdx--;
+    }
+    saveUserThemes();
+}
+
+QString ThemeManager::themesDir() const {
+    QString dir = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation)
+                  + "/themes";
+    QDir().mkpath(dir);
+    return dir;
+}
+
+void ThemeManager::loadUserThemes() {
+    m_user.clear();
+    QDir dir(themesDir());
+    for (const QString& name : dir.entryList({"*.json"}, QDir::Files)) {
+        QFile f(dir.filePath(name));
+        if (!f.open(QIODevice::ReadOnly)) continue;
+        QJsonDocument jdoc = QJsonDocument::fromJson(f.readAll());
+        if (jdoc.isObject())
+            m_user.append(Theme::fromJson(jdoc.object()));
+    }
+}
+
+void ThemeManager::saveUserThemes() const {
+    QString dir = themesDir();
+    // Remove old files
+    QDir d(dir);
+    for (const QString& name : d.entryList({"*.json"}, QDir::Files))
+        d.remove(name);
+    // Write current user themes
+    for (int i = 0; i < m_user.size(); i++) {
+        QString filename = m_user[i].name.toLower().replace(' ', '_') + ".json";
+        QFile f(dir + "/" + filename);
+        if (!f.open(QIODevice::WriteOnly)) continue;
+        f.write(QJsonDocument(m_user[i].toJson()).toJson(QJsonDocument::Indented));
+    }
+}
+
+} // namespace rcx
diff --git a/src/themes/thememanager.h b/src/themes/thememanager.h
new file mode 100644
index 0000000..3050fa6
--- /dev/null
+++ b/src/themes/thememanager.h
@@ -0,0 +1,38 @@
+#pragma once
+#include "theme.h"
+#include <QObject>
+#include <QVector>
+
+namespace rcx {
+
+class ThemeManager : public QObject {
+    Q_OBJECT
+public:
+    static ThemeManager& instance();
+
+    QVector<Theme> themes() const;
+    int currentIndex() const { return m_currentIdx; }
+    const Theme& current() const;
+
+    void setCurrent(int index);
+    void addTheme(const Theme& theme);
+    void updateTheme(int index, const Theme& theme);
+    void removeTheme(int index);
+
+    void loadUserThemes();
+    void saveUserThemes() const;
+
+signals:
+    void themeChanged(const rcx::Theme& theme);
+
+private:
+    ThemeManager();
+    QVector<Theme> m_builtIn;
+    QVector<Theme> m_user;
+    int m_currentIdx = 0;
+
+    int builtInCount() const { return m_builtIn.size(); }
+    QString themesDir() const;
+};
+
+} // namespace rcx
diff --git a/src/typeselectorpopup.cpp b/src/typeselectorpopup.cpp
index 0f570d6..28d6cc2 100644
--- a/src/typeselectorpopup.cpp
+++ b/src/typeselectorpopup.cpp
@@ -14,6 +14,7 @@
 #include <QIcon>
 #include <QApplication>
 #include <QScreen>
+#include "themes/thememanager.h"
 
 namespace rcx {
 
@@ -34,11 +35,12 @@ public:
                const QModelIndex& index) const override {
         painter->save();
 
-        // Background: editor design language greys
+        // Background: themed colors
+        const auto& t = ThemeManager::instance().current();
         if (option.state & QStyle::State_Selected)
-            painter->fillRect(option.rect, QColor("#232323"));   // M_SELECTED
+            painter->fillRect(option.rect, t.selected);
         else if (option.state & QStyle::State_MouseOver)
-            painter->fillRect(option.rect, QColor("#2b2b2b"));   // M_HOVER
+            painter->fillRect(option.rect, t.hover);
 
         int x = option.rect.x();
         int y = option.rect.y();
@@ -48,7 +50,7 @@ public:
         int row = index.row();
         if (m_filtered && row >= 0 && row < m_filtered->size()
             && (*m_filtered)[row].id == m_currentId) {
-            painter->setPen(QColor("#4ec9b0"));
+            painter->setPen(t.syntaxType);
             QFont checkFont = m_font;
             painter->setFont(checkFont);
             painter->drawText(QRect(x, y, 18, h), Qt::AlignCenter,
@@ -93,17 +95,18 @@ TypeSelectorPopup::TypeSelectorPopup(QWidget* parent)
 {
     setAttribute(Qt::WA_DeleteOnClose, false);
 
-    // Dark palette (no CSS)
+    // Theme palette
+    const auto& theme = ThemeManager::instance().current();
     QPalette pal;
-    pal.setColor(QPalette::Window,          QColor("#252526"));
-    pal.setColor(QPalette::WindowText,      QColor("#d4d4d4"));
-    pal.setColor(QPalette::Base,            QColor("#1e1e1e"));
-    pal.setColor(QPalette::AlternateBase,   QColor("#2a2d2e"));
-    pal.setColor(QPalette::Text,            QColor("#d4d4d4"));
-    pal.setColor(QPalette::Button,          QColor("#333333"));
-    pal.setColor(QPalette::ButtonText,      QColor("#d4d4d4"));
-    pal.setColor(QPalette::Highlight,       QColor("#2b2b2b"));
-    pal.setColor(QPalette::HighlightedText, QColor("#d4d4d4"));
+    pal.setColor(QPalette::Window,          theme.backgroundAlt);
+    pal.setColor(QPalette::WindowText,      theme.text);
+    pal.setColor(QPalette::Base,            theme.background);
+    pal.setColor(QPalette::AlternateBase,   theme.surface);
+    pal.setColor(QPalette::Text,            theme.text);
+    pal.setColor(QPalette::Button,          theme.button);
+    pal.setColor(QPalette::ButtonText,      theme.text);
+    pal.setColor(QPalette::Highlight,       theme.hover);
+    pal.setColor(QPalette::HighlightedText, theme.text);
     setPalette(pal);
     setAutoFillBackground(true);
 
@@ -130,7 +133,7 @@ TypeSelectorPopup::TypeSelectorPopup(QWidget* parent)
 
         m_escLabel = new QLabel(QStringLiteral("Esc"));
         QPalette dimPal = pal;
-        dimPal.setColor(QPalette::WindowText, QColor("#858585"));
+        dimPal.setColor(QPalette::WindowText, theme.textDim);
         m_escLabel->setPalette(dimPal);
         row->addWidget(m_escLabel);
 
@@ -159,7 +162,7 @@ TypeSelectorPopup::TypeSelectorPopup(QWidget* parent)
         sep->setFrameShape(QFrame::HLine);
         sep->setFrameShadow(QFrame::Plain);
         QPalette sepPal = pal;
-        sepPal.setColor(QPalette::WindowText, QColor("#3c3c3c"));
+        sepPal.setColor(QPalette::WindowText, theme.border);
         sep->setPalette(sepPal);
         sep->setFixedHeight(1);
         layout->addWidget(sep);
diff --git a/tests/test_theme.cpp b/tests/test_theme.cpp
new file mode 100644
index 0000000..790a786
--- /dev/null
+++ b/tests/test_theme.cpp
@@ -0,0 +1,132 @@
+#include <QtTest/QTest>
+#include <QtTest/QSignalSpy>
+#include <QJsonDocument>
+#include <QJsonObject>
+#include "themes/theme.h"
+#include "themes/thememanager.h"
+
+using namespace rcx;
+
+class TestTheme : public QObject {
+    Q_OBJECT
+private slots:
+    void builtInThemes() {
+        Theme dark = Theme::reclassDark();
+        QCOMPARE(dark.name, "Reclass Dark");
+        QVERIFY(dark.background.isValid());
+        QVERIFY(dark.text.isValid());
+        QVERIFY(dark.syntaxKeyword.isValid());
+        QVERIFY(dark.markerError.isValid());
+
+        Theme warm = Theme::warm();
+        QCOMPARE(warm.name, "Warm");
+        QVERIFY(warm.background.isValid());
+        QVERIFY(warm.text.isValid());
+        QCOMPARE(warm.background, QColor("#212121"));
+        QCOMPARE(warm.selection, QColor("#21213A"));
+        QCOMPARE(warm.syntaxKeyword, QColor("#AA9565"));
+        QCOMPARE(warm.syntaxType, QColor("#6B959F"));
+    }
+
+    void selectionColorFixed() {
+        Theme dark = Theme::reclassDark();
+        QCOMPARE(dark.selection, QColor("#2b2b2b"));
+        QVERIFY(dark.selection != QColor("#264f78"));
+    }
+
+    void jsonRoundTrip() {
+        Theme orig = Theme::reclassDark();
+        QJsonObject json = orig.toJson();
+        Theme loaded = Theme::fromJson(json);
+
+        QCOMPARE(loaded.name, orig.name);
+        QCOMPARE(loaded.background, orig.background);
+        QCOMPARE(loaded.text, orig.text);
+        QCOMPARE(loaded.selection, orig.selection);
+        QCOMPARE(loaded.syntaxKeyword, orig.syntaxKeyword);
+        QCOMPARE(loaded.syntaxNumber, orig.syntaxNumber);
+        QCOMPARE(loaded.syntaxString, orig.syntaxString);
+        QCOMPARE(loaded.syntaxComment, orig.syntaxComment);
+        QCOMPARE(loaded.syntaxType, orig.syntaxType);
+        QCOMPARE(loaded.markerPtr, orig.markerPtr);
+        QCOMPARE(loaded.markerError, orig.markerError);
+        QCOMPARE(loaded.indHoverSpan, orig.indHoverSpan);
+    }
+
+    void jsonRoundTripWarm() {
+        Theme orig = Theme::warm();
+        QJsonObject json = orig.toJson();
+        Theme loaded = Theme::fromJson(json);
+
+        QCOMPARE(loaded.name, orig.name);
+        QCOMPARE(loaded.background, orig.background);
+        QCOMPARE(loaded.selection, orig.selection);
+        QCOMPARE(loaded.syntaxKeyword, orig.syntaxKeyword);
+    }
+
+    void fromJsonMissingFields() {
+        QJsonObject sparse;
+        sparse["name"] = "Sparse";
+        sparse["background"] = "#ff0000";
+        Theme t = Theme::fromJson(sparse);
+
+        QCOMPARE(t.name, "Sparse");
+        QCOMPARE(t.background, QColor("#ff0000"));
+        // Missing fields fall back to reclassDark defaults
+        Theme defaults = Theme::reclassDark();
+        QCOMPARE(t.text, defaults.text);
+        QCOMPARE(t.syntaxKeyword, defaults.syntaxKeyword);
+        QCOMPARE(t.markerError, defaults.markerError);
+    }
+
+    void themeManagerHasBuiltIns() {
+        auto& tm = ThemeManager::instance();
+        auto all = tm.themes();
+        QVERIFY(all.size() >= 2);
+        QCOMPARE(all[0].name, "Reclass Dark");
+        QCOMPARE(all[1].name, "Warm");
+    }
+
+    void themeManagerSwitch() {
+        auto& tm = ThemeManager::instance();
+        QSignalSpy spy(&tm, &ThemeManager::themeChanged);
+
+        int startIdx = tm.currentIndex();
+        int target = (startIdx == 0) ? 1 : 0;
+        tm.setCurrent(target);
+
+        QCOMPARE(spy.count(), 1);
+        QCOMPARE(tm.currentIndex(), target);
+        QCOMPARE(tm.current().name, tm.themes()[target].name);
+
+        // Restore
+        tm.setCurrent(startIdx);
+    }
+
+    void themeManagerCRUD() {
+        auto& tm = ThemeManager::instance();
+        int initialCount = tm.themes().size();
+
+        // Add
+        Theme custom = Theme::reclassDark();
+        custom.name = "Test Custom";
+        custom.background = QColor("#ff0000");
+        tm.addTheme(custom);
+        QCOMPARE(tm.themes().size(), initialCount + 1);
+        QCOMPARE(tm.themes().last().name, "Test Custom");
+
+        // Update
+        int idx = tm.themes().size() - 1;
+        Theme updated = custom;
+        updated.background = QColor("#00ff00");
+        tm.updateTheme(idx, updated);
+        QCOMPARE(tm.themes()[idx].background, QColor("#00ff00"));
+
+        // Remove
+        tm.removeTheme(idx);
+        QCOMPARE(tm.themes().size(), initialCount);
+    }
+};
+
+QTEST_MAIN(TestTheme)
+#include "test_theme.moc"