diff --git a/Applications/IRCClient/IRCAppWindow.cpp b/Applications/IRCClient/IRCAppWindow.cpp
index a2671b50b3..3cb8c861ee 100644
--- a/Applications/IRCClient/IRCAppWindow.cpp
+++ b/Applications/IRCClient/IRCAppWindow.cpp
@@ -156,7 +156,7 @@ void IRCAppWindow::setup_widgets()
     auto widget = GWidget::construct();
     set_main_widget(widget);
     widget->set_fill_with_background_color(true);
-    widget->set_background_color(Color::WarmGray);
+    widget->set_background_color(SystemColor::Window);
     widget->set_layout(make<GBoxLayout>(Orientation::Vertical));
     widget->layout()->set_spacing(0);
 
diff --git a/Applications/PaintBrush/PaletteWidget.cpp b/Applications/PaintBrush/PaletteWidget.cpp
index 665a394d00..bd8775cda8 100644
--- a/Applications/PaintBrush/PaletteWidget.cpp
+++ b/Applications/PaintBrush/PaletteWidget.cpp
@@ -51,7 +51,7 @@ PaletteWidget::PaletteWidget(PaintableWidget& paintable_widget, GWidget* parent)
     set_frame_shadow(FrameShadow::Raised);
     set_frame_thickness(0);
     set_fill_with_background_color(true);
-    set_background_color(Color::WarmGray);
+    set_background_color(SystemColor::Window);
 
     set_size_policy(SizePolicy::Fill, SizePolicy::Fixed);
     set_preferred_size(0, 34);
diff --git a/Applications/PaintBrush/ToolboxWidget.cpp b/Applications/PaintBrush/ToolboxWidget.cpp
index 51c9fd0b0a..80e83d6174 100644
--- a/Applications/PaintBrush/ToolboxWidget.cpp
+++ b/Applications/PaintBrush/ToolboxWidget.cpp
@@ -35,7 +35,7 @@ private:
 ToolboxWidget::ToolboxWidget(GWidget* parent)
     : GFrame(parent)
 {
-    set_background_color(Color::WarmGray);
+    set_background_color(SystemColor::Window);
     set_fill_with_background_color(true);
 
     set_frame_thickness(1);
diff --git a/Applications/SystemMonitor/NetworkStatisticsWidget.cpp b/Applications/SystemMonitor/NetworkStatisticsWidget.cpp
index e9001cd6ef..c7eb3c3932 100644
--- a/Applications/SystemMonitor/NetworkStatisticsWidget.cpp
+++ b/Applications/SystemMonitor/NetworkStatisticsWidget.cpp
@@ -11,7 +11,7 @@ NetworkStatisticsWidget::NetworkStatisticsWidget(GWidget* parent)
         set_layout(make<GBoxLayout>(Orientation::Vertical));
         layout()->set_margins({ 4, 4, 4, 4 });
         set_fill_with_background_color(true);
-        set_background_color(Color::WarmGray);
+        set_background_color(SystemColor::Window);
 
         auto adapters_group_box = GGroupBox::construct("Adapters", this);
         adapters_group_box->set_layout(make<GBoxLayout>(Orientation::Vertical));
diff --git a/Applications/SystemMonitor/main.cpp b/Applications/SystemMonitor/main.cpp
index edc690251c..f67bde0f16 100644
--- a/Applications/SystemMonitor/main.cpp
+++ b/Applications/SystemMonitor/main.cpp
@@ -53,7 +53,7 @@ int main(int argc, char** argv)
     auto keeper = GWidget::construct();
     keeper->set_layout(make<GBoxLayout>(Orientation::Vertical));
     keeper->set_fill_with_background_color(true);
-    keeper->set_background_color(Color::WarmGray);
+    keeper->set_background_color(SystemColor::Window);
     keeper->layout()->set_margins({ 4, 4, 4, 4 });
 
     auto tabwidget = GTabWidget::construct(keeper);
@@ -355,7 +355,7 @@ NonnullRefPtr<GWidget> build_graphs_tab()
 
     graphs_container->on_first_show = [](auto& self) {
         self.set_fill_with_background_color(true);
-        self.set_background_color(Color::WarmGray);
+        self.set_background_color(SystemColor::Window);
         self.set_layout(make<GBoxLayout>(Orientation::Vertical));
         self.layout()->set_margins({ 4, 4, 4, 4 });
 
diff --git a/Applications/Terminal/main.cpp b/Applications/Terminal/main.cpp
index 17bd9dd2d0..528bc65ddf 100644
--- a/Applications/Terminal/main.cpp
+++ b/Applications/Terminal/main.cpp
@@ -124,7 +124,7 @@ RefPtr<GWindow> create_settings_window(TerminalWidget& terminal, RefPtr<CConfigF
     slider_container->set_preferred_size(100, 50);
     auto slider = GSlider::construct(Orientation::Horizontal, slider_container);
     slider->set_fill_with_background_color(true);
-    slider->set_background_color(Color::WarmGray);
+    slider->set_background_color(SystemColor::Window);
 
     slider->on_value_changed = [&terminal, &config](int value) {
         terminal.set_opacity(value);
diff --git a/Base/home/anon/WindowManager.ini b/Base/home/anon/WindowManager.ini
index 4ad27fcfe9..385d063a1b 100644
--- a/Base/home/anon/WindowManager.ini
+++ b/Base/home/anon/WindowManager.ini
@@ -2,6 +2,9 @@
 Width=1024
 Height=768
 
+[Theme]
+Name=Default
+
 [Cursor]
 Arrow=/res/cursors/arrow.png
 ResizeH=/res/cursors/resize-horizontal.png
@@ -14,26 +17,6 @@ Move=/res/cursors/move.png
 Hand=/res/cursors/hand.png
 Drag=/res/cursors/drag.png
 
-[Colors]
-Background=50,50,50
-ActiveWindowBorder=110,34,9
-ActiveWindowBorder2=244,202,158
-ActiveWindowTitle=255,255,255
-
-InactiveWindowBorder=128,128,128
-InactiveWindowBorder2=192,192,192
-InactiveWindowTitle=213,208,199
-
-MovingWindowBorder=161,50,13
-MovingWindowBorder2=250,220,187
-MovingWindowTitle=255,255,255
-
-HighlightWindowBorder=161,13,13
-HighlightWindowBorder2=250,187,187
-HighlightWindowTitle=255,255,255
-
-MenuSelectionColor=132,53,26
-
 [Input]
 DoubleClickSpeed=250
 
diff --git a/Base/res/themes/Default.ini b/Base/res/themes/Default.ini
new file mode 100644
index 0000000000..526ec3adba
--- /dev/null
+++ b/Base/res/themes/Default.ini
@@ -0,0 +1,32 @@
+[Colors]
+DesktopBackground=#404040
+
+ActiveWindowBorder1=#6e2209
+ActiveWindowBorder2=#f4ca9e
+ActiveWindowTitle=white
+
+InactiveWindowBorder1=#808080
+InactiveWindowBorder2=#c0c0c0
+InactiveWindowTitle=#d5d0c7
+
+MovingWindowBorder1=#a1320d
+MovingWindowBorder2=#fadcbb
+MovingWindowTitle=white
+
+HighlightWindowBorder1=#a10d0d
+HighlightWindowBorder2=#fabbbb
+HighlightWindowTitle=white
+
+MenuBase=white
+MenuStripe=#bbb7b0
+MenuSelection=#ad714f
+
+Window=#d4d0c8
+Text=black
+Base=white
+
+ThreedHighlight=white
+ThreedShadow1=#808080
+ThreedShadow2=#404040
+
+HoverHighlight=#e3dfdb
diff --git a/Base/res/themes/Xmas.ini b/Base/res/themes/Xmas.ini
new file mode 100644
index 0000000000..c11a1be78f
--- /dev/null
+++ b/Base/res/themes/Xmas.ini
@@ -0,0 +1,33 @@
+[Colors]
+DesktopBackground=#313819
+
+ActiveWindowBorder1=#731013
+ActiveWindowBorder2=#ee3532
+ActiveWindowTitle=white
+
+InactiveWindowBorder1=#734546
+InactiveWindowBorder2=#ee908f
+InactiveWindowTitle=white
+
+MovingWindowBorder1=#a76f24
+MovingWindowBorder2=#eec666
+MovingWindowTitle=white
+
+HighlightWindowBorder1=#a76f24
+HighlightWindowBorder2=#eec666
+HighlightWindowTitle=white
+
+MenuBase=#57691f
+MenuStripe=#2b3018
+MenuSelection=#ff8742
+
+Window=#d46c64
+Text=black
+Base=#d3d7c4
+
+ThreedHighlight=#e69e99
+ThreedShadow1=#a24841
+ThreedShadow2=#882d26
+
+HoverHighlight=#e6e5e2
+
diff --git a/DevTools/HackStudio/FormWidget.cpp b/DevTools/HackStudio/FormWidget.cpp
index 7ae3c74096..08506beade 100644
--- a/DevTools/HackStudio/FormWidget.cpp
+++ b/DevTools/HackStudio/FormWidget.cpp
@@ -7,7 +7,7 @@ FormWidget::FormWidget(FormEditorWidget& parent)
     : GWidget(&parent)
 {
     set_fill_with_background_color(true);
-    set_background_color(Color::WarmGray);
+    set_background_color(SystemColor::Window);
     set_relative_rect(5, 5, 400, 300);
 
     set_greedy_for_hits(true);
diff --git a/DevTools/VisualBuilder/VBForm.cpp b/DevTools/VisualBuilder/VBForm.cpp
index 11a716fe05..5181414c38 100644
--- a/DevTools/VisualBuilder/VBForm.cpp
+++ b/DevTools/VisualBuilder/VBForm.cpp
@@ -25,7 +25,7 @@ VBForm::VBForm(const String& name, GWidget* parent)
 {
     s_current = this;
     set_fill_with_background_color(true);
-    set_background_color(Color::WarmGray);
+    set_background_color(SystemColor::Window);
     set_greedy_for_hits(true);
 
     m_context_menu = GMenu::construct();
diff --git a/Games/Minesweeper/Field.cpp b/Games/Minesweeper/Field.cpp
index 10cdb9b115..70e4f2a0c2 100644
--- a/Games/Minesweeper/Field.cpp
+++ b/Games/Minesweeper/Field.cpp
@@ -121,7 +121,7 @@ Field::Field(GLabel& flag_label, GLabel& time_label, GButton& face_button, GWidg
         m_number_bitmap[i] = GraphicsBitmap::load_from_file(String::format("/res/icons/minesweeper/%u.png", i + 1));
 
     set_fill_with_background_color(true);
-    set_background_color(Color::WarmGray);
+    set_background_color(SystemColor::Window);
     reset();
 
     m_face_button.on_click = [this](auto&) { reset(); };
diff --git a/Libraries/LibC/SharedBuffer.cpp b/Libraries/LibC/SharedBuffer.cpp
index 30fff21a46..86c50edd05 100644
--- a/Libraries/LibC/SharedBuffer.cpp
+++ b/Libraries/LibC/SharedBuffer.cpp
@@ -25,6 +25,17 @@ bool SharedBuffer::share_with(pid_t peer)
     return true;
 }
 
+bool SharedBuffer::share_globally()
+{
+    int ret = share_buffer_globally(shared_buffer_id());
+    if (ret < 0) {
+        perror("share_buffer_globally");
+        return false;
+    }
+    return true;
+}
+
+
 RefPtr<SharedBuffer> SharedBuffer::create_from_shared_buffer_id(int shared_buffer_id)
 {
     void* data = get_shared_buffer(shared_buffer_id);
diff --git a/Libraries/LibC/SharedBuffer.h b/Libraries/LibC/SharedBuffer.h
index e79abad00b..75b3a2a158 100644
--- a/Libraries/LibC/SharedBuffer.h
+++ b/Libraries/LibC/SharedBuffer.h
@@ -9,6 +9,7 @@ public:
     static RefPtr<SharedBuffer> create_from_shared_buffer_id(int);
     ~SharedBuffer();
 
+    bool share_globally();
     bool share_with(pid_t);
     int shared_buffer_id() const { return m_shared_buffer_id; }
     void seal();
diff --git a/Libraries/LibCore/CConfigFile.cpp b/Libraries/LibCore/CConfigFile.cpp
index cef1d1cf4d..dc7a727885 100644
--- a/Libraries/LibCore/CConfigFile.cpp
+++ b/Libraries/LibCore/CConfigFile.cpp
@@ -110,36 +110,6 @@ int CConfigFile::read_num_entry(const String& group, const String& key, int defa
     return value;
 }
 
-Color CConfigFile::read_color_entry(const String& group, const String& key, Color default_value) const
-{
-    if (!has_key(group, key)) {
-        const_cast<CConfigFile&>(*this).write_color_entry(group, key, default_value);
-        return default_value;
-    }
-
-    auto shades = read_entry(group, key).split(',');
-    if (shades.size() < 3)
-        return default_value;
-    bool ok1 = true,
-         ok2 = true,
-         ok3 = true,
-         ok4 = true;
-    Color value;
-    if (shades.size() == 3) {
-        value = Color(shades[0].to_uint(ok1),
-            shades[1].to_uint(ok2),
-            shades[2].to_uint(ok3));
-    } else {
-        value = Color(shades[0].to_uint(ok1),
-            shades[1].to_uint(ok2),
-            shades[2].to_uint(ok3),
-            shades[3].to_uint(ok4));
-    }
-    if (!(ok1 && ok2 && ok3 && ok4))
-        return default_value;
-    return value;
-}
-
 bool CConfigFile::read_bool_entry(const String& group, const String& key, bool default_value) const
 {
     return read_entry(group, key, default_value ? "1" : "0") == "1";
diff --git a/Libraries/LibCore/CConfigFile.h b/Libraries/LibCore/CConfigFile.h
index 6b84947dc5..f21d35f849 100644
--- a/Libraries/LibCore/CConfigFile.h
+++ b/Libraries/LibCore/CConfigFile.h
@@ -23,7 +23,6 @@ public:
     String read_entry(const String& group, const String& key, const String& default_vaule = String()) const;
     int read_num_entry(const String& group, const String& key, int default_value = 0) const;
     bool read_bool_entry(const String& group, const String& key, bool default_value = false) const;
-    Color read_color_entry(const String& group, const String& key, Color default_value) const;
 
     void write_entry(const String& group, const String& key, const String& value);
     void write_num_entry(const String& group, const String& key, int value);
diff --git a/Libraries/LibDraw/Color.cpp b/Libraries/LibDraw/Color.cpp
index fa32743e5e..4324ac440c 100644
--- a/Libraries/LibDraw/Color.cpp
+++ b/Libraries/LibDraw/Color.cpp
@@ -1,8 +1,85 @@
 #include <AK/Assertions.h>
 #include <LibDraw/Color.h>
+#include <LibDraw/SystemTheme.h>
 #include <ctype.h>
 #include <stdio.h>
 
+Color::Color(SystemColor system_color)
+{
+    auto& theme = current_system_theme();
+    switch (system_color) {
+    case SystemColor::Window:
+        m_value = theme.window.value();
+        break;
+    case SystemColor::Text:
+        m_value = theme.text.value();
+        break;
+    case SystemColor::Base:
+        m_value = theme.base.value();
+        break;
+    case SystemColor::ThreedShadow1:
+        m_value = theme.threed_shadow1.value();
+        break;
+    case SystemColor::ThreedShadow2:
+        m_value = theme.threed_shadow2.value();
+        break;
+    case SystemColor::ThreedHighlight:
+        m_value = theme.threed_highlight.value();
+        break;
+    case SystemColor::HoverHighlight:
+        m_value = theme.hover_highlight.value();
+        break;
+    case SystemColor::DesktopBackground:
+        m_value = theme.desktop_background.value();
+        break;
+    case SystemColor::ActiveWindowBorder1:
+        m_value = theme.active_window_border1.value();
+        break;
+    case SystemColor::ActiveWindowBorder2:
+        m_value = theme.active_window_border2.value();
+        break;
+    case SystemColor::ActiveWindowTitle:
+        m_value = theme.active_window_title.value();
+        break;
+    case SystemColor::InactiveWindowBorder1:
+        m_value = theme.inactive_window_border1.value();
+        break;
+    case SystemColor::InactiveWindowBorder2:
+        m_value = theme.inactive_window_border2.value();
+        break;
+    case SystemColor::InactiveWindowTitle:
+        m_value = theme.inactive_window_title.value();
+        break;
+    case SystemColor::MovingWindowBorder1:
+        m_value = theme.moving_window_border1.value();
+        break;
+    case SystemColor::MovingWindowBorder2:
+        m_value = theme.moving_window_border2.value();
+        break;
+    case SystemColor::MovingWindowTitle:
+        m_value = theme.moving_window_title.value();
+        break;
+    case SystemColor::HighlightWindowBorder1:
+        m_value = theme.highlight_window_border1.value();
+        break;
+    case SystemColor::HighlightWindowBorder2:
+        m_value = theme.highlight_window_border2.value();
+        break;
+    case SystemColor::HighlightWindowTitle:
+        m_value = theme.highlight_window_title.value();
+        break;
+    case SystemColor::MenuStripe:
+        m_value = theme.menu_stripe.value();
+        break;
+    case SystemColor::MenuBase:
+        m_value = theme.menu_base.value();
+        break;
+    case SystemColor::MenuSelection:
+        m_value = theme.menu_selection.value();
+        break;
+    }
+}
+
 Color::Color(NamedColor named)
 {
     struct {
diff --git a/Libraries/LibDraw/Color.h b/Libraries/LibDraw/Color.h
index f412a29ba9..5b991d05d3 100644
--- a/Libraries/LibDraw/Color.h
+++ b/Libraries/LibDraw/Color.h
@@ -1,7 +1,7 @@
 #pragma once
 
-#include <AK/String.h>
 #include <AK/Optional.h>
+#include <AK/String.h>
 #include <AK/Types.h>
 
 typedef u32 RGBA32;
@@ -11,6 +11,32 @@ inline constexpr u32 make_rgb(u8 r, u8 g, u8 b)
     return ((r << 16) | (g << 8) | b);
 }
 
+enum class SystemColor {
+    DesktopBackground,
+    ActiveWindowBorder1,
+    ActiveWindowBorder2,
+    ActiveWindowTitle,
+    InactiveWindowBorder1,
+    InactiveWindowBorder2,
+    InactiveWindowTitle,
+    MovingWindowBorder1,
+    MovingWindowBorder2,
+    MovingWindowTitle,
+    HighlightWindowBorder1,
+    HighlightWindowBorder2,
+    HighlightWindowTitle,
+    MenuStripe,
+    MenuBase,
+    MenuSelection,
+    Window,
+    Text,
+    Base,
+    ThreedHighlight,
+    ThreedShadow1,
+    ThreedShadow2,
+    HoverHighlight,
+};
+
 class Color {
 public:
     enum NamedColor {
@@ -39,6 +65,7 @@ public:
 
     Color() {}
     Color(NamedColor);
+    Color(SystemColor);
     Color(u8 r, u8 g, u8 b)
         : m_value(0xff000000 | (r << 16) | (g << 8) | b)
     {
diff --git a/Libraries/LibDraw/Makefile b/Libraries/LibDraw/Makefile
index 8923d22f9c..d6bc6f0b22 100644
--- a/Libraries/LibDraw/Makefile
+++ b/Libraries/LibDraw/Makefile
@@ -10,6 +10,7 @@ OBJS = \
     ImageDecoder.o \
     Rect.o \
     StylePainter.o \
+    SystemTheme.o \
     Emoji.o
 
 LIBRARY = libdraw.a
diff --git a/Libraries/LibDraw/StylePainter.cpp b/Libraries/LibDraw/StylePainter.cpp
index 8ef6bbabc3..62e4796c10 100644
--- a/Libraries/LibDraw/StylePainter.cpp
+++ b/Libraries/LibDraw/StylePainter.cpp
@@ -3,10 +3,10 @@
 
 void StylePainter::paint_tab_button(Painter& painter, const Rect& rect, bool active, bool hovered, bool enabled)
 {
-    Color base_color = Color::WarmGray;
-    Color highlight_color2 = Color::from_rgb(0xe8e7e4);
-    Color shadow_color1 = Color::from_rgb(0x808080);
-    Color shadow_color2 = Color::from_rgb(0x404040);
+    Color base_color = SystemColor::Window;
+    Color highlight_color2 = SystemColor::ThreedHighlight;
+    Color shadow_color1 = SystemColor::ThreedShadow1;
+    Color shadow_color2 = SystemColor::ThreedShadow2;
 
     if (hovered && enabled && !active)
         base_color = StylePainter::hover_highlight_color();
@@ -44,16 +44,16 @@ void StylePainter::paint_tab_button(Painter& painter, const Rect& rect, bool act
 
 static void paint_button_new(Painter& painter, const Rect& rect, bool pressed, bool checked, bool hovered, bool enabled)
 {
-    Color button_color = Color::WarmGray;
-    Color highlight_color2 = Color::from_rgb(0xe8e7e4);
-    Color shadow_color1 = Color::from_rgb(0x808080);
-    Color shadow_color2 = Color::from_rgb(0x404040);
+    Color button_color = SystemColor::Window;
+    Color highlight_color2 = SystemColor::ThreedHighlight;
+    Color shadow_color1 = SystemColor::ThreedShadow1;
+    Color shadow_color2 = SystemColor::ThreedShadow2;
 
     if (checked && enabled) {
         if (hovered)
-            button_color = Color::from_rgb(0xe3dfdb);
+            button_color = SystemColor::HoverHighlight;
         else
-            button_color = Color::from_rgb(0xd6d2ce);
+            button_color = SystemColor::Window;
     } else if (hovered && enabled)
         button_color = StylePainter::hover_highlight_color();
 
@@ -92,7 +92,7 @@ void StylePainter::paint_button(Painter& painter, const Rect& rect, ButtonStyle
     if (button_style == ButtonStyle::Normal)
         return paint_button_new(painter, rect, pressed, checked, hovered, enabled);
 
-    Color button_color = checked ? Color::from_rgb(0xd6d2ce) : Color::WarmGray;
+    Color button_color = SystemColor::Window;
     Color highlight_color = Color::White;
     Color shadow_color = Color(96, 96, 96);
 
@@ -129,12 +129,12 @@ void StylePainter::paint_button(Painter& painter, const Rect& rect, ButtonStyle
 
 void StylePainter::paint_surface(Painter& painter, const Rect& rect, bool paint_vertical_lines, bool paint_top_line)
 {
-    painter.fill_rect({ rect.x(), rect.y() + 1, rect.width(), rect.height() - 2 }, Color::WarmGray);
-    painter.draw_line(rect.top_left(), rect.top_right(), paint_top_line ? Color::White : Color::WarmGray);
-    painter.draw_line(rect.bottom_left(), rect.bottom_right(), Color::MidGray);
+    painter.fill_rect({ rect.x(), rect.y() + 1, rect.width(), rect.height() - 2 }, SystemColor::Window);
+    painter.draw_line(rect.top_left(), rect.top_right(), paint_top_line ? SystemColor::ThreedHighlight : SystemColor::Window);
+    painter.draw_line(rect.bottom_left(), rect.bottom_right(), SystemColor::ThreedShadow1);
     if (paint_vertical_lines) {
-        painter.draw_line(rect.top_left().translated(0, 1), rect.bottom_left().translated(0, -1), Color::White);
-        painter.draw_line(rect.top_right(), rect.bottom_right().translated(0, -1), Color::MidGray);
+        painter.draw_line(rect.top_left().translated(0, 1), rect.bottom_left().translated(0, -1), SystemColor::ThreedHighlight);
+        painter.draw_line(rect.top_right(), rect.bottom_right().translated(0, -1), SystemColor::ThreedShadow1);
     }
 }
 
@@ -142,12 +142,12 @@ void StylePainter::paint_frame(Painter& painter, const Rect& rect, FrameShape sh
 {
     Color top_left_color;
     Color bottom_right_color;
-    Color dark_shade = Color::from_rgb(0x808080);
-    Color light_shade = Color::from_rgb(0xffffff);
+    Color dark_shade = SystemColor::ThreedShadow1;
+    Color light_shade = SystemColor::ThreedHighlight;
 
     if (shape == FrameShape::Container && thickness >= 2) {
         if (shadow == FrameShadow::Raised) {
-            dark_shade = Color::from_rgb(0x404040);
+            dark_shade = SystemColor::ThreedShadow2;
         }
     }
 
@@ -175,10 +175,10 @@ void StylePainter::paint_frame(Painter& painter, const Rect& rect, FrameShape sh
     if (shape == FrameShape::Container && thickness >= 2) {
         Color top_left_color;
         Color bottom_right_color;
-        Color dark_shade = Color::from_rgb(0x404040);
-        Color light_shade = Color::WarmGray;
+        Color dark_shade = SystemColor::ThreedShadow2;
+        Color light_shade = SystemColor::Window;
         if (shadow == FrameShadow::Raised) {
-            dark_shade = Color::from_rgb(0x808080);
+            dark_shade = SystemColor::ThreedShadow1;
             top_left_color = light_shade;
             bottom_right_color = dark_shade;
         } else if (shadow == FrameShadow::Sunken) {
@@ -207,10 +207,10 @@ void StylePainter::paint_frame(Painter& painter, const Rect& rect, FrameShape sh
 
 void StylePainter::paint_window_frame(Painter& painter, const Rect& rect)
 {
-    Color base_color = Color::WarmGray;
-    Color dark_shade = Color::from_rgb(0x404040);
-    Color mid_shade = Color::from_rgb(0x808080);
-    Color light_shade = Color::from_rgb(0xffffff);
+    Color base_color = SystemColor::Window;
+    Color dark_shade = SystemColor::ThreedShadow2;
+    Color mid_shade = SystemColor::ThreedShadow1;
+    Color light_shade = SystemColor::ThreedHighlight;
 
     painter.draw_line(rect.top_left(), rect.top_right(), base_color);
     painter.draw_line(rect.top_left().translated(0, 1), rect.bottom_left(), base_color);
diff --git a/Libraries/LibDraw/StylePainter.h b/Libraries/LibDraw/StylePainter.h
index 82bf8b0b24..d40ad6d336 100644
--- a/Libraries/LibDraw/StylePainter.h
+++ b/Libraries/LibDraw/StylePainter.h
@@ -32,5 +32,5 @@ public:
     static void paint_window_frame(Painter&, const Rect&);
     static void paint_progress_bar(Painter&, const Rect&, int min, int max, int value, const StringView& text = {});
 
-    static Color hover_highlight_color() { return Color::from_rgb(0xe6e5e2); }
+    static Color hover_highlight_color() { return SystemColor::HoverHighlight; }
 };
diff --git a/Libraries/LibDraw/SystemTheme.cpp b/Libraries/LibDraw/SystemTheme.cpp
new file mode 100644
index 0000000000..c5e05e1ebd
--- /dev/null
+++ b/Libraries/LibDraw/SystemTheme.cpp
@@ -0,0 +1,73 @@
+#include <LibCore/CConfigFile.h>
+#include <LibDraw/SystemTheme.h>
+
+static SystemTheme dummy_theme;
+static const SystemTheme* theme_page = &dummy_theme;
+static RefPtr<SharedBuffer> theme_buffer;
+
+const SystemTheme& current_system_theme()
+{
+    ASSERT(theme_page);
+    return *theme_page;
+}
+
+int current_system_theme_buffer_id()
+{
+    ASSERT(theme_buffer);
+    return theme_buffer->shared_buffer_id();
+}
+
+void set_system_theme(SharedBuffer& buffer)
+{
+    theme_buffer = buffer;
+    theme_page = (SystemTheme*)theme_buffer->data();
+}
+
+RefPtr<SharedBuffer> load_system_theme(const String& path)
+{
+    auto file = CConfigFile::open(path);
+    auto buffer = SharedBuffer::create_with_size(sizeof(SystemTheme));
+
+    dbg() << "Created shared buffer with id " << buffer->shared_buffer_id();
+
+    auto* data = (SystemTheme*)buffer->data();
+
+    auto get = [&](auto& name) {
+        auto color_string = file->read_entry("Colors", name);
+        auto color = Color::from_string(color_string);
+        if (!color.has_value())
+            return Color(Color::Black);
+        dbg() << "Parsed system color '" << name << "' = " << color.value();
+        return color.value();
+    };
+
+    data->desktop_background = get("DesktopBackground");
+    data->threed_highlight = get("ThreedHighlight");
+    data->threed_shadow1 = get("ThreedShadow1");
+    data->threed_shadow2 = get("ThreedShadow2");
+    data->hover_highlight = get("HoverHighlight");
+    data->window = get("Window");
+    data->text = get("Text");
+    data->base = get("Base");
+    data->desktop_background = get("DesktopBackground");
+    data->active_window_border1 = get("ActiveWindowBorder1");
+    data->active_window_border2 = get("ActiveWindowBorder2");
+    data->active_window_title = get("ActiveWindowTitle");
+    data->inactive_window_border1 = get("InactiveWindowBorder1");
+    data->inactive_window_border2 = get("InactiveWindowBorder2");
+    data->inactive_window_title = get("InactiveWindowTitle");
+    data->moving_window_border1 = get("MovingWindowBorder1");
+    data->moving_window_border2 = get("MovingWindowBorder2");
+    data->moving_window_title = get("MovingWindowTitle");
+    data->highlight_window_border1 = get("HighlightWindowBorder1");
+    data->highlight_window_border2 = get("HighlightWindowBorder2");
+    data->highlight_window_title = get("HighlightWindowTitle");
+    data->menu_stripe = get("MenuStripe");
+    data->menu_base = get("MenuBase");
+    data->menu_selection = get("MenuSelection");
+
+    buffer->seal();
+    buffer->share_globally();
+
+    return buffer;
+}
diff --git a/Libraries/LibDraw/SystemTheme.h b/Libraries/LibDraw/SystemTheme.h
new file mode 100644
index 0000000000..2fa7a635b0
--- /dev/null
+++ b/Libraries/LibDraw/SystemTheme.h
@@ -0,0 +1,44 @@
+#pragma once
+
+#include <AK/Types.h>
+#include <LibC/SharedBuffer.h>
+#include <LibDraw/Color.h>
+
+struct SystemTheme {
+    Color desktop_background;
+
+    Color active_window_border1;
+    Color active_window_border2;
+    Color active_window_title;
+
+    Color inactive_window_border1;
+    Color inactive_window_border2;
+    Color inactive_window_title;
+
+    Color moving_window_border1;
+    Color moving_window_border2;
+    Color moving_window_title;
+
+    Color highlight_window_border1;
+    Color highlight_window_border2;
+    Color highlight_window_title;
+
+    Color menu_stripe;
+    Color menu_base;
+    Color menu_selection;
+
+    Color window;
+    Color text;
+    Color base;
+
+    Color threed_highlight;
+    Color threed_shadow1;
+    Color threed_shadow2;
+
+    Color hover_highlight;
+};
+
+const SystemTheme& current_system_theme();
+int current_system_theme_buffer_id();
+void set_system_theme(SharedBuffer&);
+RefPtr<SharedBuffer> load_system_theme(const String& path);
diff --git a/Libraries/LibGUI/GAbstractColumnView.cpp b/Libraries/LibGUI/GAbstractColumnView.cpp
index 28b52692da..98ffcfff5a 100644
--- a/Libraries/LibGUI/GAbstractColumnView.cpp
+++ b/Libraries/LibGUI/GAbstractColumnView.cpp
@@ -99,9 +99,9 @@ void GAbstractColumnView::paint_headers(GPainter& painter)
     if (!headers_visible())
         return;
     int exposed_width = max(content_size().width(), width());
-    painter.fill_rect({ 0, 0, exposed_width, header_height() }, Color::WarmGray);
-    painter.draw_line({ 0, 0 }, { exposed_width - 1, 0 }, Color::White);
-    painter.draw_line({ 0, header_height() - 1 }, { exposed_width - 1, header_height() - 1 }, Color::MidGray);
+    painter.fill_rect({ 0, 0, exposed_width, header_height() }, SystemColor::Window);
+    painter.draw_line({ 0, 0 }, { exposed_width - 1, 0 }, SystemColor::ThreedHighlight);
+    painter.draw_line({ 0, header_height() - 1 }, { exposed_width - 1, header_height() - 1 }, SystemColor::ThreedShadow1);
     int x_offset = 0;
     int column_count = model()->column_count();
     for (int column_index = 0; column_index < column_count; ++column_index) {
@@ -129,7 +129,7 @@ void GAbstractColumnView::paint_headers(GPainter& painter)
         auto text_rect = cell_rect.translated(horizontal_padding(), 0);
         if (pressed)
             text_rect.move_by(1, 1);
-        painter.draw_text(text_rect, text, header_font(), TextAlignment::CenterLeft, Color::Black);
+        painter.draw_text(text_rect, text, header_font(), TextAlignment::CenterLeft, SystemColor::Text);
         x_offset += column_width + horizontal_padding() * 2;
     }
 }
diff --git a/Libraries/LibGUI/GCheckBox.cpp b/Libraries/LibGUI/GCheckBox.cpp
index bca4cd8a97..46fd2a2b62 100644
--- a/Libraries/LibGUI/GCheckBox.cpp
+++ b/Libraries/LibGUI/GCheckBox.cpp
@@ -54,7 +54,7 @@ void GCheckBox::paint_event(GPaintEvent& event)
         0, height() / 2 - s_box_height / 2 - 1,
         s_box_width, s_box_height
     };
-    painter.fill_rect(box_rect, Color::White);
+    painter.fill_rect(box_rect, SystemColor::Base);
     StylePainter::paint_frame(painter, box_rect, FrameShape::Container, FrameShadow::Sunken, 2);
 
     if (is_being_pressed())
@@ -63,7 +63,7 @@ void GCheckBox::paint_event(GPaintEvent& event)
     if (is_checked()) {
         if (!s_checked_bitmap)
             s_checked_bitmap = &CharacterBitmap::create_from_ascii(s_checked_bitmap_data, s_checked_bitmap_width, s_checked_bitmap_height).leak_ref();
-        painter.draw_bitmap(box_rect.shrunken(4, 4).location(), *s_checked_bitmap, foreground_color());
+        painter.draw_bitmap(box_rect.shrunken(4, 4).location(), *s_checked_bitmap, SystemColor::Text);
     }
 
     paint_text(painter, text_rect, font(), TextAlignment::TopLeft);
diff --git a/Libraries/LibGUI/GFilePicker.cpp b/Libraries/LibGUI/GFilePicker.cpp
index 6480f8c603..28d19d197d 100644
--- a/Libraries/LibGUI/GFilePicker.cpp
+++ b/Libraries/LibGUI/GFilePicker.cpp
@@ -58,7 +58,7 @@ GFilePicker::GFilePicker(Mode mode, const StringView& file_name, const StringVie
     horizontal_container->set_layout(make<GBoxLayout>(Orientation::Horizontal));
     horizontal_container->layout()->set_margins({ 4, 4, 4, 4 });
     horizontal_container->set_fill_with_background_color(true);
-    horizontal_container->set_background_color(Color::WarmGray);
+    horizontal_container->set_background_color(SystemColor::Window);
 
     auto vertical_container = GWidget::construct(horizontal_container.ptr());
     vertical_container->set_layout(make<GBoxLayout>(Orientation::Vertical));
diff --git a/Libraries/LibGUI/GGroupBox.cpp b/Libraries/LibGUI/GGroupBox.cpp
index 3ce063f248..3d97790262 100644
--- a/Libraries/LibGUI/GGroupBox.cpp
+++ b/Libraries/LibGUI/GGroupBox.cpp
@@ -12,7 +12,7 @@ GGroupBox::GGroupBox(const StringView& title, GWidget* parent)
     , m_title(title)
 {
     set_fill_with_background_color(true);
-    set_background_color(Color::WarmGray);
+    set_background_color(SystemColor::Window);
 }
 
 GGroupBox::~GGroupBox()
diff --git a/Libraries/LibGUI/GItemView.cpp b/Libraries/LibGUI/GItemView.cpp
index 3c880d220e..183afb4e4b 100644
--- a/Libraries/LibGUI/GItemView.cpp
+++ b/Libraries/LibGUI/GItemView.cpp
@@ -191,7 +191,7 @@ void GItemView::paint_event(GPaintEvent& event)
     GPainter painter(*this);
     painter.add_clip_rect(widget_inner_rect());
     painter.add_clip_rect(event.rect());
-    painter.fill_rect(event.rect(), Color::White);
+    painter.fill_rect(event.rect(), SystemColor::Base);
     painter.translate(-horizontal_scrollbar().value(), -vertical_scrollbar().value());
 
     auto column_metadata = model()->column_metadata(m_model_column);
@@ -203,7 +203,7 @@ void GItemView::paint_event(GPaintEvent& event)
         if (is_selected_item) {
             background_color = is_focused() ? Color::from_rgb(0x84351a) : Color::from_rgb(0x606060);
         } else {
-            background_color = Color::White;
+            background_color = SystemColor::Base;
         }
 
         Rect item_rect = this->item_rect(item_index);
@@ -230,7 +230,7 @@ void GItemView::paint_event(GPaintEvent& event)
         if (is_selected_item)
             text_color = Color::White;
         else
-            text_color = model()->data(model_index, GModel::Role::ForegroundColor).to_color(Color::Black);
+            text_color = model()->data(model_index, GModel::Role::ForegroundColor).to_color(SystemColor::Text);
         painter.fill_rect(text_rect, background_color);
         painter.draw_text(text_rect, item_text.to_string(), font, TextAlignment::Center, text_color, TextElision::Right);
     };
diff --git a/Libraries/LibGUI/GListView.cpp b/Libraries/LibGUI/GListView.cpp
index b0aea7f0b0..29bf44aa64 100644
--- a/Libraries/LibGUI/GListView.cpp
+++ b/Libraries/LibGUI/GListView.cpp
@@ -109,7 +109,7 @@ void GListView::paint_event(GPaintEvent& event)
             if (alternating_row_colors() && (painted_item_index % 2))
                 background_color = Color(210, 210, 210);
             else
-                background_color = Color::White;
+                background_color = SystemColor::Base;
         }
 
         auto column_metadata = model()->column_metadata(m_model_column);
@@ -140,7 +140,7 @@ void GListView::paint_event(GPaintEvent& event)
     };
 
     Rect unpainted_rect(0, painted_item_index * item_height(), exposed_width, height());
-    painter.fill_rect(unpainted_rect, Color::White);
+    painter.fill_rect(unpainted_rect, SystemColor::Base);
 }
 
 int GListView::item_count() const
diff --git a/Libraries/LibGUI/GSplitter.cpp b/Libraries/LibGUI/GSplitter.cpp
index 2f82f5219e..b1dc224462 100644
--- a/Libraries/LibGUI/GSplitter.cpp
+++ b/Libraries/LibGUI/GSplitter.cpp
@@ -8,7 +8,7 @@ GSplitter::GSplitter(Orientation orientation, GWidget* parent)
 {
     set_layout(make<GBoxLayout>(orientation));
     set_fill_with_background_color(true);
-    set_background_color(Color::WarmGray);
+    set_background_color(SystemColor::Window);
     layout()->set_spacing(3);
 }
 
@@ -25,7 +25,7 @@ void GSplitter::enter_event(CEvent&)
 
 void GSplitter::leave_event(CEvent&)
 {
-    set_background_color(Color::WarmGray);
+    set_background_color(SystemColor::Window);
     if (!m_resizing)
         window()->set_override_cursor(GStandardCursor::None);
     update();
diff --git a/Libraries/LibGUI/GTabWidget.cpp b/Libraries/LibGUI/GTabWidget.cpp
index a5dc20864f..7166d3b454 100644
--- a/Libraries/LibGUI/GTabWidget.cpp
+++ b/Libraries/LibGUI/GTabWidget.cpp
@@ -7,7 +7,7 @@ GTabWidget::GTabWidget(GWidget* parent)
     : GWidget(parent)
 {
     set_fill_with_background_color(true);
-    set_background_color(Color::WarmGray);
+    set_background_color(SystemColor::Window);
 }
 
 GTabWidget::~GTabWidget()
diff --git a/Libraries/LibGUI/GTableView.cpp b/Libraries/LibGUI/GTableView.cpp
index 3bb8588daf..820e5ed3fd 100644
--- a/Libraries/LibGUI/GTableView.cpp
+++ b/Libraries/LibGUI/GTableView.cpp
@@ -25,7 +25,7 @@ void GTableView::paint_event(GPaintEvent& event)
     GPainter painter(*this);
     painter.add_clip_rect(frame_inner_rect());
     painter.add_clip_rect(event.rect());
-    painter.fill_rect(event.rect(), Color::White);
+    painter.fill_rect(event.rect(), SystemColor::Base);
     painter.translate(frame_thickness(), frame_thickness());
     painter.translate(-horizontal_scrollbar().value(), -vertical_scrollbar().value());
 
@@ -60,7 +60,7 @@ void GTableView::paint_event(GPaintEvent& event)
                 background_color = Color(220, 220, 220);
                 key_column_background_color = Color(200, 200, 200);
             } else {
-                background_color = Color::White;
+                background_color = SystemColor::Base;
                 key_column_background_color = Color(220, 220, 220);
             }
         }
@@ -105,7 +105,7 @@ void GTableView::paint_event(GPaintEvent& event)
     };
 
     Rect unpainted_rect(0, header_height() + painted_item_index * item_height(), exposed_width, height());
-    painter.fill_rect(unpainted_rect, Color::White);
+    painter.fill_rect(unpainted_rect, SystemColor::Base);
 
     // Untranslate the painter vertically and do the column headers.
     painter.translate(0, vertical_scrollbar().value());
diff --git a/Libraries/LibGUI/GToolBar.cpp b/Libraries/LibGUI/GToolBar.cpp
index 59b32c2725..85b468929b 100644
--- a/Libraries/LibGUI/GToolBar.cpp
+++ b/Libraries/LibGUI/GToolBar.cpp
@@ -93,5 +93,5 @@ void GToolBar::paint_event(GPaintEvent& event)
     if (m_has_frame)
         StylePainter::paint_surface(painter, rect(), x() != 0, y() != 0);
     else
-        painter.fill_rect(event.rect(), Color::WarmGray);
+        painter.fill_rect(event.rect(), background_color());
 }
diff --git a/Libraries/LibGUI/GTreeView.cpp b/Libraries/LibGUI/GTreeView.cpp
index e0c3283245..2269f45a64 100644
--- a/Libraries/LibGUI/GTreeView.cpp
+++ b/Libraries/LibGUI/GTreeView.cpp
@@ -146,7 +146,7 @@ void GTreeView::paint_event(GPaintEvent& event)
     GPainter painter(*this);
     painter.add_clip_rect(frame_inner_rect());
     painter.add_clip_rect(event.rect());
-    painter.fill_rect(event.rect(), Color::White);
+    painter.fill_rect(event.rect(), SystemColor::Base);
 
     if (!model())
         return;
@@ -192,7 +192,7 @@ void GTreeView::paint_event(GPaintEvent& event)
                 background_color = Color(220, 220, 220);
                 key_column_background_color = Color(200, 200, 200);
             } else {
-                background_color = Color::White;
+                background_color = SystemColor::Base;
                 key_column_background_color = Color(220, 220, 220);
             }
         }
diff --git a/Libraries/LibGUI/GWidget.cpp b/Libraries/LibGUI/GWidget.cpp
index 9dcaf7cdce..66e926acb1 100644
--- a/Libraries/LibGUI/GWidget.cpp
+++ b/Libraries/LibGUI/GWidget.cpp
@@ -68,8 +68,8 @@ GWidget::GWidget(GWidget* parent)
     : CObject(parent, true)
     , m_font(Font::default_font())
 {
-    m_background_color = Color::WarmGray;
-    m_foreground_color = Color::Black;
+    m_background_color = SystemColor::Window;
+    m_foreground_color = SystemColor::Text;
 }
 
 GWidget::~GWidget()
diff --git a/Libraries/LibGUI/GWindow.cpp b/Libraries/LibGUI/GWindow.cpp
index 5f5c69240f..c9d1511392 100644
--- a/Libraries/LibGUI/GWindow.cpp
+++ b/Libraries/LibGUI/GWindow.cpp
@@ -686,3 +686,10 @@ void GWindow::schedule_relayout()
         m_layout_pending = false;
     });
 }
+
+void GWindow::update_all_windows(Badge<GWindowServerConnection>)
+{
+    for (auto* window : all_windows) {
+        window->update();
+    }
+}
diff --git a/Libraries/LibGUI/GWindow.h b/Libraries/LibGUI/GWindow.h
index 82575d4a14..b345bda92e 100644
--- a/Libraries/LibGUI/GWindow.h
+++ b/Libraries/LibGUI/GWindow.h
@@ -1,15 +1,17 @@
 #pragma once
 
-#include <AK/String.h>
+#include <AK/Badge.h>
 #include <AK/HashMap.h>
+#include <AK/String.h>
 #include <AK/WeakPtr.h>
 #include <LibCore/CObject.h>
 #include <LibDraw/GraphicsBitmap.h>
 #include <LibDraw/Rect.h>
 #include <LibGUI/GWindowType.h>
 
-class GWidget;
 class GWMEvent;
+class GWidget;
+class GWindowServerConnection;
 
 enum class GStandardCursor {
     None = 0,
@@ -133,6 +135,8 @@ public:
 
     void schedule_relayout();
 
+    static void update_all_windows(Badge<GWindowServerConnection>);
+
 protected:
     GWindow(CObject* parent = nullptr);
     virtual void wm_event(GWMEvent&);
diff --git a/Libraries/LibGUI/GWindowServerConnection.cpp b/Libraries/LibGUI/GWindowServerConnection.cpp
index 8e2daca6e9..d7f98e8ce8 100644
--- a/Libraries/LibGUI/GWindowServerConnection.cpp
+++ b/Libraries/LibGUI/GWindowServerConnection.cpp
@@ -1,3 +1,4 @@
+#include <LibDraw/SystemTheme.h>
 #include <LibGUI/GAction.h>
 #include <LibGUI/GApplication.h>
 #include <LibGUI/GClipboard.h>
@@ -19,13 +20,27 @@ GWindowServerConnection& GWindowServerConnection::the()
     return *s_connection;
 }
 
+static void set_system_theme_from_shared_buffer_id(int id)
+{
+    auto system_theme = SharedBuffer::create_from_shared_buffer_id(id);
+    ASSERT(system_theme);
+    set_system_theme(*system_theme);
+}
+
 void GWindowServerConnection::handshake()
 {
     auto response = send_sync<WindowServer::Greet>();
     set_my_client_id(response->client_id());
+    set_system_theme_from_shared_buffer_id(response->system_theme_buffer_id());
     GDesktop::the().did_receive_screen_rect({}, response->screen_rect());
 }
 
+void GWindowServerConnection::handle(const WindowClient::UpdateSystemTheme& message)
+{
+    set_system_theme_from_shared_buffer_id(message.system_theme_buffer_id());
+    GWindow::update_all_windows({});
+}
+
 void GWindowServerConnection::handle(const WindowClient::Paint& message)
 {
 #ifdef GEVENTLOOP_DEBUG
diff --git a/Libraries/LibGUI/GWindowServerConnection.h b/Libraries/LibGUI/GWindowServerConnection.h
index 56fc8b0c21..1647d5fc85 100644
--- a/Libraries/LibGUI/GWindowServerConnection.h
+++ b/Libraries/LibGUI/GWindowServerConnection.h
@@ -44,4 +44,5 @@ private:
     virtual void handle(const WindowClient::DragDropped&) override;
     virtual void handle(const WindowClient::DragAccepted&) override;
     virtual void handle(const WindowClient::DragCancelled&) override;
+    virtual void handle(const WindowClient::UpdateSystemTheme&) override;
 };
diff --git a/Servers/WindowServer/WSClientConnection.cpp b/Servers/WindowServer/WSClientConnection.cpp
index fc507b4613..d91186513e 100644
--- a/Servers/WindowServer/WSClientConnection.cpp
+++ b/Servers/WindowServer/WSClientConnection.cpp
@@ -1,5 +1,6 @@
 #include <LibC/SharedBuffer.h>
 #include <LibDraw/GraphicsBitmap.h>
+#include <LibDraw/SystemTheme.h>
 #include <SharedBuffer.h>
 #include <WindowServer/WSClientConnection.h>
 #include <WindowServer/WSClipboard.h>
@@ -605,7 +606,7 @@ void WSClientConnection::handle(const WindowServer::WM_SetWindowMinimized& messa
 
 OwnPtr<WindowServer::GreetResponse> WSClientConnection::handle(const WindowServer::Greet&)
 {
-    return make<WindowServer::GreetResponse>(client_id(), WSScreen::the().rect());
+    return make<WindowServer::GreetResponse>(client_id(), WSScreen::the().rect(), current_system_theme_buffer_id());
 }
 
 bool WSClientConnection::is_showing_modal_window() const
diff --git a/Servers/WindowServer/WSCompositor.cpp b/Servers/WindowServer/WSCompositor.cpp
index 459cc301ed..ee166e4df3 100644
--- a/Servers/WindowServer/WSCompositor.cpp
+++ b/Servers/WindowServer/WSCompositor.cpp
@@ -113,7 +113,7 @@ void WSCompositor::compose()
         if (wm.any_opaque_window_contains_rect(dirty_rect))
             continue;
         // FIXME: If the wallpaper is opaque, no need to fill with color!
-        m_back_painter->fill_rect(dirty_rect, wm.m_background_color);
+        m_back_painter->fill_rect(dirty_rect, SystemColor::DesktopBackground);
         if (m_wallpaper) {
             if (m_wallpaper_mode == WallpaperMode::Simple) {
                 m_back_painter->blit(dirty_rect.location(), *m_wallpaper, dirty_rect);
diff --git a/Servers/WindowServer/WSMenu.cpp b/Servers/WindowServer/WSMenu.cpp
index 71186e4fa9..46e1a3e35c 100644
--- a/Servers/WindowServer/WSMenu.cpp
+++ b/Servers/WindowServer/WSMenu.cpp
@@ -126,12 +126,14 @@ WSWindow& WSMenu::ensure_menu_window()
 
 void WSMenu::draw()
 {
+    m_theme_index_at_last_paint = WSWindowManager::the().theme_index();
+
     ASSERT(menu_window());
     ASSERT(menu_window()->backing_store());
     Painter painter(*menu_window()->backing_store());
 
     Rect rect { {}, menu_window()->size() };
-    painter.fill_rect(rect.shrunken(6, 6), Color::White);
+    painter.fill_rect(rect.shrunken(6, 6), SystemColor::MenuBase);
     StylePainter::paint_window_frame(painter, rect);
     int width = this->width();
 
@@ -146,15 +148,15 @@ void WSMenu::draw()
     }
 
     Rect stripe_rect { frame_thickness(), frame_thickness(), s_stripe_width, height() - frame_thickness() * 2 };
-    painter.fill_rect(stripe_rect, Color::WarmGray);
-    painter.draw_line(stripe_rect.top_right(), stripe_rect.bottom_right(), Color::from_rgb(0xbbb7b0));
+    painter.fill_rect(stripe_rect, SystemColor::MenuStripe);
+    painter.draw_line(stripe_rect.top_right(), stripe_rect.bottom_right(), Color(SystemColor::MenuStripe).darkened());
 
     for (auto& item : m_items) {
         if (item.type() == WSMenuItem::Text) {
             Color text_color = Color::Black;
             if (&item == m_hovered_item && item.is_enabled()) {
-                painter.fill_rect(item.rect(), Color::from_rgb(0xad714f));
-                painter.draw_rect(item.rect(), Color::from_rgb(0x793016));
+                painter.fill_rect(item.rect(), SystemColor::MenuSelection);
+                painter.draw_rect(item.rect(), Color(SystemColor::MenuSelection).darkened());
                 text_color = Color::White;
             } else if (!item.is_enabled()) {
                 text_color = Color::MidGray;
@@ -164,10 +166,10 @@ void WSMenu::draw()
                 Rect checkmark_rect { item.rect().x() + 7, 0, s_checked_bitmap_width, s_checked_bitmap_height };
                 checkmark_rect.center_vertically_within(text_rect);
                 Rect checkbox_rect = checkmark_rect.inflated(4, 4);
-                painter.fill_rect(checkbox_rect, Color::White);
+                painter.fill_rect(checkbox_rect, SystemColor::Base);
                 StylePainter::paint_frame(painter, checkbox_rect, FrameShape::Container, FrameShadow::Sunken, 2);
                 if (item.is_checked()) {
-                    painter.draw_bitmap(checkmark_rect.location(), *s_checked_bitmap, Color::Black);
+                    painter.draw_bitmap(checkmark_rect.location(), *s_checked_bitmap, SystemColor::Text);
                 }
             } else if (item.icon()) {
                 Rect icon_rect { item.rect().x() + 3, 0, s_item_icon_width, s_item_icon_width };
@@ -274,11 +276,19 @@ void WSMenu::close()
     WSWindowManager::the().menu_manager().close_menu_and_descendants(*this);
 }
 
+void WSMenu::redraw_if_theme_changed()
+{
+    if (m_theme_index_at_last_paint != WSWindowManager::the().theme_index())
+        redraw();
+}
+
 void WSMenu::popup(const Point& position, bool is_submenu)
 {
     ASSERT(!is_empty());
 
     auto& window = ensure_menu_window();
+    redraw_if_theme_changed();
+
     const int margin = 30;
     Point adjusted_pos = position;
     if (adjusted_pos.x() + window.width() >= WSScreen::the().width() - margin) {
diff --git a/Servers/WindowServer/WSMenu.h b/Servers/WindowServer/WSMenu.h
index fc72a71b81..7f9afb946a 100644
--- a/Servers/WindowServer/WSMenu.h
+++ b/Servers/WindowServer/WSMenu.h
@@ -78,6 +78,8 @@ public:
 
     bool is_menu_ancestor_of(const WSMenu&) const;
 
+    void redraw_if_theme_changed();
+
 private:
     virtual void event(CEvent&) override;
 
@@ -92,4 +94,5 @@ private:
     WSMenuItem* m_hovered_item { nullptr };
     NonnullOwnPtrVector<WSMenuItem> m_items;
     RefPtr<WSWindow> m_menu_window;
+    int m_theme_index_at_last_paint { -1 };
 };
diff --git a/Servers/WindowServer/WSMenuManager.cpp b/Servers/WindowServer/WSMenuManager.cpp
index cccb76782c..51a9f6e99b 100644
--- a/Servers/WindowServer/WSMenuManager.cpp
+++ b/Servers/WindowServer/WSMenuManager.cpp
@@ -83,14 +83,14 @@ void WSMenuManager::draw()
 
     Painter painter(*window().backing_store());
 
-    painter.fill_rect(menubar_rect, Color::WarmGray);
-    painter.draw_line({ 0, menubar_rect.bottom() }, { menubar_rect.right(), menubar_rect.bottom() }, Color::MidGray);
+    painter.fill_rect(menubar_rect, SystemColor::Window);
+    painter.draw_line({ 0, menubar_rect.bottom() }, { menubar_rect.right(), menubar_rect.bottom() }, SystemColor::ThreedShadow1);
     int index = 0;
     wm.for_each_active_menubar_menu([&](WSMenu& menu) {
-        Color text_color = Color::Black;
+        Color text_color = SystemColor::Text;
         if (is_open(menu)) {
-            painter.fill_rect(menu.rect_in_menubar(), Color::from_rgb(0xad714f));
-            painter.draw_rect(menu.rect_in_menubar(), Color::from_rgb(0x793016));
+            painter.fill_rect(menu.rect_in_menubar(), SystemColor::MenuSelection);
+            painter.draw_rect(menu.rect_in_menubar(), Color(SystemColor::MenuSelection).darkened());
             text_color = Color::White;
         }
         painter.draw_text(
@@ -103,7 +103,7 @@ void WSMenuManager::draw()
         return IterationDecision::Continue;
     });
 
-    painter.draw_text(m_username_rect, m_username, Font::default_bold_font(), TextAlignment::CenterRight, Color::Black);
+    painter.draw_text(m_username_rect, m_username, Font::default_bold_font(), TextAlignment::CenterRight, SystemColor::Text);
 
     time_t now = time(nullptr);
     auto* tm = localtime(&now);
@@ -115,7 +115,7 @@ void WSMenuManager::draw()
         tm->tm_min,
         tm->tm_sec);
 
-    painter.draw_text(m_time_rect, time_text, wm.font(), TextAlignment::CenterRight, Color::Black);
+    painter.draw_text(m_time_rect, time_text, wm.font(), TextAlignment::CenterRight, SystemColor::Text);
 
     for (auto& applet : m_applets) {
         if (!applet)
@@ -182,6 +182,7 @@ void WSMenuManager::handle_menu_mouse_event(WSMenu& menu, const WSMouseEvent& ev
             return;
         close_everyone();
         if (!menu.is_empty()) {
+            menu.redraw_if_theme_changed();
             auto& menu_window = menu.ensure_menu_window();
             menu_window.move_to({ menu.rect_in_menubar().x(), menu.rect_in_menubar().bottom() + 2 });
             menu_window.set_visible(true);
diff --git a/Servers/WindowServer/WSWindowFrame.cpp b/Servers/WindowServer/WSWindowFrame.cpp
index 3b4801a26c..44853d3ec1 100644
--- a/Servers/WindowServer/WSWindowFrame.cpp
+++ b/Servers/WindowServer/WSWindowFrame.cpp
@@ -170,21 +170,21 @@ void WSWindowFrame::paint(Painter& painter)
     auto& wm = WSWindowManager::the();
 
     if (&window == wm.m_highlight_window) {
-        border_color = wm.m_highlight_window_border_color;
-        border_color2 = wm.m_highlight_window_border_color2;
-        title_color = wm.m_highlight_window_title_color;
+        border_color = SystemColor::HighlightWindowBorder1;
+        border_color2 = SystemColor::HighlightWindowBorder2;
+        title_color = SystemColor::HighlightWindowTitle;
     } else if (&window == wm.m_move_window) {
-        border_color = wm.m_moving_window_border_color;
-        border_color2 = wm.m_moving_window_border_color2;
-        title_color = wm.m_moving_window_title_color;
+        border_color = SystemColor::MovingWindowBorder1;
+        border_color2 = SystemColor::MovingWindowBorder2;
+        title_color = SystemColor::MovingWindowTitle;
     } else if (&window == wm.m_active_window) {
-        border_color = wm.m_active_window_border_color;
-        border_color2 = wm.m_active_window_border_color2;
-        title_color = wm.m_active_window_title_color;
+        border_color = SystemColor::ActiveWindowBorder1;
+        border_color2 = SystemColor::ActiveWindowBorder2;
+        title_color = SystemColor::ActiveWindowTitle;
     } else {
-        border_color = wm.m_inactive_window_border_color;
-        border_color2 = wm.m_inactive_window_border_color2;
-        title_color = wm.m_inactive_window_title_color;
+        border_color = SystemColor::InactiveWindowBorder1;
+        border_color2 = SystemColor::InactiveWindowBorder2;
+        title_color = SystemColor::InactiveWindowTitle;
     }
 
     StylePainter::paint_window_frame(painter, outer_rect);
diff --git a/Servers/WindowServer/WSWindowManager.cpp b/Servers/WindowServer/WSWindowManager.cpp
index d4b56e953a..be1f2fb71f 100644
--- a/Servers/WindowServer/WSWindowManager.cpp
+++ b/Servers/WindowServer/WSWindowManager.cpp
@@ -6,6 +6,7 @@
 #include "WSMenuItem.h"
 #include "WSScreen.h"
 #include "WSWindow.h"
+#include <AK/FileSystemPath.h>
 #include <AK/LogStream.h>
 #include <AK/QuickSort.h>
 #include <AK/StdLibExtras.h>
@@ -17,6 +18,7 @@
 #include <LibDraw/PNGLoader.h>
 #include <LibDraw/Painter.h>
 #include <LibDraw/StylePainter.h>
+#include <LibDraw/SystemTheme.h>
 #include <WindowServer/WSButton.h>
 #include <WindowServer/WSClientConnection.h>
 #include <WindowServer/WSCursor.h>
@@ -47,19 +49,21 @@ WSWindowManager::WSWindowManager()
     reload_config(false);
 
     HashTable<String> seen_app_categories;
-    CDirIterator dt("/res/apps", CDirIterator::SkipDots);
-    while (dt.has_next()) {
-        auto af_name = dt.next_path();
-        auto af_path = String::format("/res/apps/%s", af_name.characters());
-        auto af = CConfigFile::open(af_path);
-        if (!af->has_key("App", "Name") || !af->has_key("App", "Executable"))
-            continue;
-        auto app_name = af->read_entry("App", "Name");
-        auto app_executable = af->read_entry("App", "Executable");
-        auto app_category = af->read_entry("App", "Category");
-        auto app_icon_path = af->read_entry("Icons", "16x16");
-        m_apps.append({ app_executable, app_name, app_icon_path, app_category });
-        seen_app_categories.set(app_category);
+    {
+        CDirIterator dt("/res/apps", CDirIterator::SkipDots);
+        while (dt.has_next()) {
+            auto af_name = dt.next_path();
+            auto af_path = String::format("/res/apps/%s", af_name.characters());
+            auto af = CConfigFile::open(af_path);
+            if (!af->has_key("App", "Name") || !af->has_key("App", "Executable"))
+                continue;
+            auto app_name = af->read_entry("App", "Name");
+            auto app_executable = af->read_entry("App", "Executable");
+            auto app_category = af->read_entry("App", "Category");
+            auto app_icon_path = af->read_entry("Icons", "16x16");
+            m_apps.append({ app_executable, app_name, app_icon_path, app_category });
+            seen_app_categories.set(app_category);
+        }
     }
 
     Vector<String> sorted_app_categories;
@@ -98,8 +102,56 @@ WSWindowManager::WSWindowManager()
         parent_menu->add_item(make<WSMenuItem>(*m_system_menu, app_identifier++, app.name, String(), true, false, false, load_png(app.icon_path)));
     }
 
+    m_system_menu->add_item(make<WSMenuItem>(*m_system_menu, WSMenuItem::Separator));
+
+    m_themes_menu = WSMenu::construct(nullptr, 9000, "Themes");
+
+    auto themes_menu_item = make<WSMenuItem>(*m_system_menu, 100, "Themes");
+    themes_menu_item->set_submenu_id(m_themes_menu->menu_id());
+    m_system_menu->add_item(move(themes_menu_item));
+
+    {
+        CDirIterator dt("/res/themes", CDirIterator::SkipDots);
+        while (dt.has_next()) {
+            auto theme_name = dt.next_path();
+            auto theme_path = String::format("/res/themes/%s", theme_name.characters());
+            m_themes.append({ FileSystemPath(theme_name).title(), theme_path });
+        }
+        quick_sort(m_themes.begin(), m_themes.end(), [](auto& a, auto& b) { return a.name < b.name; });
+    }
+
+    {
+        int theme_identifier = 9000;
+        for (auto& theme : m_themes) {
+            m_themes_menu->add_item(make<WSMenuItem>(*m_themes_menu, theme_identifier++, theme.name));
+        }
+    }
+
+    m_themes_menu->on_item_activation = [this](WSMenuItem& item) {
+        auto& theme = m_themes[(int)item.identifier() - 9000];
+        auto new_theme = load_system_theme(theme.path);
+        ASSERT(new_theme);
+        set_system_theme(*new_theme);
+        HashTable<WSClientConnection*> notified_clients;
+        for_each_window([&](WSWindow& window) {
+            if (window.client()) {
+                if (!notified_clients.contains(window.client())) {
+                    window.client()->post_message(WindowClient::UpdateSystemTheme(current_system_theme_buffer_id()));
+                    notified_clients.set(window.client());
+                }
+            }
+            return IterationDecision::Continue;
+        });
+        ++m_theme_index;
+        auto wm_config = CConfigFile::get_for_app("WindowManager");
+        wm_config->write_entry("Theme", "Name", theme.name);
+        wm_config->sync();
+        invalidate();
+    };
+
     m_system_menu->add_item(make<WSMenuItem>(*m_system_menu, WSMenuItem::Separator));
     m_system_menu->add_item(make<WSMenuItem>(*m_system_menu, 100, "Reload WM Config File"));
+
     m_system_menu->add_item(make<WSMenuItem>(*m_system_menu, WSMenuItem::Separator));
     m_system_menu->add_item(make<WSMenuItem>(*m_system_menu, 200, "About...", String(), true, false, false, load_png("/res/icons/16x16/ladybug.png")));
     m_system_menu->add_item(make<WSMenuItem>(*m_system_menu, WSMenuItem::Separator));
@@ -186,26 +238,6 @@ void WSWindowManager::reload_config(bool set_screen)
     m_disallowed_cursor = get_cursor("Disallowed");
     m_move_cursor = get_cursor("Move");
     m_drag_cursor = get_cursor("Drag");
-
-    m_background_color = m_wm_config->read_color_entry("Colors", "Background", Color::Red);
-
-    m_active_window_border_color = m_wm_config->read_color_entry("Colors", "ActiveWindowBorder", Color::Red);
-    m_active_window_border_color2 = m_wm_config->read_color_entry("Colors", "ActiveWindowBorder2", Color::Red);
-    m_active_window_title_color = m_wm_config->read_color_entry("Colors", "ActiveWindowTitle", Color::Red);
-
-    m_inactive_window_border_color = m_wm_config->read_color_entry("Colors", "InactiveWindowBorder", Color::Red);
-    m_inactive_window_border_color2 = m_wm_config->read_color_entry("Colors", "InactiveWindowBorder2", Color::Red);
-    m_inactive_window_title_color = m_wm_config->read_color_entry("Colors", "InactiveWindowTitle", Color::Red);
-
-    m_moving_window_border_color = m_wm_config->read_color_entry("Colors", "MovingWindowBorder", Color::Red);
-    m_moving_window_border_color2 = m_wm_config->read_color_entry("Colors", "MovingWindowBorder2", Color::Red);
-    m_moving_window_title_color = m_wm_config->read_color_entry("Colors", "MovingWindowTitle", Color::Red);
-
-    m_highlight_window_border_color = m_wm_config->read_color_entry("Colors", "HighlightWindowBorder", Color::Red);
-    m_highlight_window_border_color2 = m_wm_config->read_color_entry("Colors", "HighlightWindowBorder2", Color::Red);
-    m_highlight_window_title_color = m_wm_config->read_color_entry("Colors", "HighlightWindowTitle", Color::Red);
-
-    m_menu_selection_color = m_wm_config->read_color_entry("Colors", "MenuSelectionColor", Color::Red);
 }
 
 const Font& WSWindowManager::font() const
@@ -1183,6 +1215,8 @@ Rect WSWindowManager::maximized_window_rect(const WSWindow& window) const
 
 WSMenu* WSWindowManager::find_internal_menu_by_id(int menu_id)
 {
+    if (m_themes_menu->menu_id() == menu_id)
+        return m_themes_menu.ptr();
     for (auto& it : m_app_category_menus) {
         if (menu_id == it.value->menu_id())
             return it.value;
diff --git a/Servers/WindowServer/WSWindowManager.h b/Servers/WindowServer/WSWindowManager.h
index 6faaa6699e..2f19aa9b7d 100644
--- a/Servers/WindowServer/WSWindowManager.h
+++ b/Servers/WindowServer/WSWindowManager.h
@@ -159,6 +159,8 @@ public:
 
     WSMenu* find_internal_menu_by_id(int);
 
+    int theme_index() const { return m_theme_index; }
+
 private:
     NonnullRefPtr<WSCursor> get_cursor(const String& name);
     NonnullRefPtr<WSCursor> get_cursor(const String& name, const Point& hotspot);
@@ -266,6 +268,8 @@ private:
     Color m_menu_selection_color;
     WeakPtr<WSMenuBar> m_current_menubar;
 
+    int m_theme_index { 0 };
+
     WSWindowSwitcher m_switcher;
     WSMenuManager m_menu_manager;
 
@@ -283,6 +287,13 @@ private:
     Vector<AppMetadata> m_apps;
     HashMap<String, NonnullRefPtr<WSMenu>> m_app_category_menus;
 
+    struct ThemeMetadata {
+        String name;
+        String path;
+    };
+    Vector<ThemeMetadata> m_themes;
+    RefPtr<WSMenu> m_themes_menu;
+
     WeakPtr<WSClientConnection> m_dnd_client;
     String m_dnd_text;
     String m_dnd_data_type;
diff --git a/Servers/WindowServer/WindowClient.ipc b/Servers/WindowServer/WindowClient.ipc
index 8006d3d814..9e345ef52d 100644
--- a/Servers/WindowServer/WindowClient.ipc
+++ b/Servers/WindowServer/WindowClient.ipc
@@ -32,4 +32,6 @@ endpoint WindowClient = 4
     DragCancelled() =|
 
     DragDropped(i32 window_id, Point mouse_position, String text, String data_type, String data) =|
+
+    UpdateSystemTheme(i32 system_theme_buffer_id) =|
 }
diff --git a/Servers/WindowServer/WindowServer.ipc b/Servers/WindowServer/WindowServer.ipc
index 64988712f8..0a831081d3 100644
--- a/Servers/WindowServer/WindowServer.ipc
+++ b/Servers/WindowServer/WindowServer.ipc
@@ -1,6 +1,6 @@
 endpoint WindowServer = 2
 {
-    Greet() => (i32 client_id, Rect screen_rect)
+    Greet() => (i32 client_id, Rect screen_rect, i32 system_theme_buffer_id)
 
     CreateMenubar() => (i32 menubar_id)
     DestroyMenubar(i32 menubar_id) => ()
diff --git a/Servers/WindowServer/main.cpp b/Servers/WindowServer/main.cpp
index 542998a3d0..c629f9464d 100644
--- a/Servers/WindowServer/main.cpp
+++ b/Servers/WindowServer/main.cpp
@@ -1,4 +1,5 @@
 #include <LibCore/CConfigFile.h>
+#include <LibDraw/SystemTheme.h>
 #include <WindowServer/WSCompositor.h>
 #include <WindowServer/WSEventLoop.h>
 #include <WindowServer/WSScreen.h>
@@ -18,9 +19,15 @@ int main(int, char**)
         return 1;
     }
 
+    auto wm_config = CConfigFile::get_for_app("WindowManager");
+    auto theme_name = wm_config->read_entry("Theme", "Name", "Default");
+
+    auto theme = load_system_theme(String::format("/res/themes/%s.ini", theme_name.characters()));
+    ASSERT(theme);
+    set_system_theme(*theme);
+
     WSEventLoop loop;
 
-    auto wm_config = CConfigFile::get_for_app("WindowManager");
     WSScreen screen(wm_config->read_num_entry("Screen", "Width", 1024),
         wm_config->read_num_entry("Screen", "Height", 768));
     WSCompositor::the();