diff --git a/lib/cyberarm_engine/game_state.rb b/lib/cyberarm_engine/game_state.rb
index a122266..c2e6179 100644
--- a/lib/cyberarm_engine/game_state.rb
+++ b/lib/cyberarm_engine/game_state.rb
@@ -4,15 +4,16 @@ module CyberarmEngine
     include DSL
 
     attr_accessor :options, :global_pause, :active_container, :active_grid
-    attr_reader :game_objects
+    attr_reader :game_objects, :containers
 
     def initialize(options={})
       @options = options
       @game_objects = []
       @global_pause = false
 
-      @active_container = nil
-      @active_grid      = nil
+      @root_container = Stack.new(x: 0, y: 0, width: $window.width, height: $window.height)
+      @game_objects << @root_container
+      @containers     = [@root_container]
 
       setup
     end
diff --git a/lib/cyberarm_engine/ui/button.rb b/lib/cyberarm_engine/ui/button.rb
index 8fd261a..4d4eb8d 100644
--- a/lib/cyberarm_engine/ui/button.rb
+++ b/lib/cyberarm_engine/ui/button.rb
@@ -1,48 +1,44 @@
 module CyberarmEngine
-  class Button < Element
-    def initialize(text, options = {}, block = nil)
-      super(options, block)
-
-      @text = Text.new(text, font: @options[:font], color: @options[:interactive_stroke], size: @options[:text_size], shadow: @options[:text_shadow])
-
-      return self
-    end
-
+  class Button < Label
     def draw
       @text.draw
 
-      $window.draw_rect(@x, @y, width, height, @options[:background], @z+1)
+      $window.draw_rect(relative_x, relative_y, width, height, @options[:background], @z+1)
 
       if mouse_over? && $window.button_down?(Gosu::MsLeft)
-        $window.draw_rect(@x+1, @y+1, width-2, height-2, @options[:interactive_active_background], @z+2)
+        $window.draw_rect(
+          relative_x+@options[:interactive_border_size],
+          relative_y+@options[:interactive_border_size],
+          width-(@options[:interactive_border_size]*2),
+          height-(@options[:interactive_border_size]*2),
+          @options[:interactive_active_background],
+          @z+2
+        )
+
+        @text.color = @options[:interactive_active_stroke]
       elsif mouse_over?
-        $window.draw_rect(@x+1, @y+1, width-2, height-2, @options[:interactive_hover_background], @z+2)
+        $window.draw_rect(
+          relative_x+@options[:interactive_border_size],
+          relative_y+@options[:interactive_border_size],
+          width-(@options[:interactive_border_size]*2),
+          height-(@options[:interactive_border_size]*2),
+          @options[:interactive_hover_background],
+          @z+2
+        )
         # show_tooltip
+        @text.color = @options[:interactive_stroke]
       else
-        $window.draw_rect(@x+1, @y+1, width-2, height-2, @options[:interactive_background], @z+2)
+        $window.draw_rect(
+          relative_x+@options[:interactive_border_size],
+          relative_y+@options[:interactive_border_size],
+          width-(@options[:interactive_border_size]*2),
+          height-(@options[:interactive_border_size]*2),
+          @options[:interactive_background],
+          @z+2
+        )
+
+        @text.color = @options[:interactive_stroke]
       end
     end
-
-    def button_up(id)
-      case id
-      when Gosu::MsLeft
-        if mouse_over?
-          @block.call(self) if @block
-        end
-      end
-    end
-
-    def recalculate
-      @width = @text.width
-      @height= @text.height
-
-      @text.x = @x + @padding
-      @text.y = @y + @padding
-      @text.z = @z + 3
-    end
-
-    def value
-      @text.text
-    end
   end
 end
\ No newline at end of file
diff --git a/lib/cyberarm_engine/ui/check_box.rb b/lib/cyberarm_engine/ui/check_box.rb
index 256b418..3edc579 100644
--- a/lib/cyberarm_engine/ui/check_box.rb
+++ b/lib/cyberarm_engine/ui/check_box.rb
@@ -1,36 +1,25 @@
 module CyberarmEngine
-  class CheckBox < Element
+  class CheckBox < Button
     def initialize(options, block = nil)
-      super(options, block)
+      super(options[:checkmark], options, block)
       @checked = options[:checked] || false
-
-      @text = Text.new("X", font: @options[:font], color: @options[:interactive_stroke], size: @options[:text_size], shadow: @options[:text_shadow])
-
-      return self
-    end
-
-    def draw
-      $window.draw_rect(@x, @y, width, height, @options[:background], @z+1)
-
-      if mouse_over?
-        $window.draw_rect(@x+1, @y+1, width-2, height-2, @options[:interactive_hover_background], @z+2)
+      if @checked
+        @text.text = options[:checkmark]
       else
-        if @checked
-          $window.draw_rect(@x+1, @y+1, width-2, height-2, @options[:interactive_active_background], @z+2)
-        else
-          $window.draw_rect(@x+1, @y+1, width-2, height-2, @options[:interactive_background], @z + 2)
-        end
+        @text.text = ""
       end
 
-      @text.draw if @checked
+      return self
     end
 
     def button_up(id)
       if mouse_over? && id == Gosu::MsLeft
         if @checked
           @checked = false
+          @text.text = ""
         else
           @checked = true
+          @text.text = @options[:checkmark]
         end
 
         @block.call(self) if @block
@@ -38,12 +27,9 @@ module CyberarmEngine
     end
 
     def recalculate
-      @width = @text.width
-      @height= @text.height
+      super
 
-      @text.x = @x + @padding
-      @text.y = @y + @padding
-      @text.z = @z + 3
+      @width = @text.textobject.text_width(@options[:checkmark])
     end
 
     def value
diff --git a/lib/cyberarm_engine/ui/container.rb b/lib/cyberarm_engine/ui/container.rb
index c19b606..ee5c03d 100644
--- a/lib/cyberarm_engine/ui/container.rb
+++ b/lib/cyberarm_engine/ui/container.rb
@@ -2,17 +2,15 @@ module CyberarmEngine
   class Container
     include Common
 
-    attr_accessor :stroke_color, :fill_color, :background_color
-    attr_reader :elements, :x, :y, :z, :width, :height, :options
+    attr_accessor :stroke_color, :fill_color, :background_color, :x, :y, :z, :width, :height
+    attr_reader :elements, :children, :options
     attr_reader :scroll_x, :scroll_y, :internal_width, :internal_height
 
     def initialize(options = {}, block = nil)
-      options[:parent].active_container = self
-
       options = {
         x: 0, y: 0, z: 0,
-        width: $window.width, height: $window.height
-      }.merge!(options)
+        width: 0, height: 0
+      }.merge(options)
 
       x = options.dig(:x)
       y = options.dig(:y)
@@ -32,23 +30,43 @@ module CyberarmEngine
       @scroll_x, @scroll_y = 0, 0
       @scroll_speed = 10
 
+      @block = block
       @options = options
+      @parent = options[:parent] || nil
 
       @text_color = options[:text_color] || Gosu::Color::WHITE
       @background_color = Gosu::Color::NONE
+
       @elements = []
+      @children = []
 
-      block.call(self) if block
-
-      options[:parent].active_container = nil
-
-      recalculate
+      @theme = {}
 
       return self
     end
 
+    def build
+      @block.call(self) if @block
+
+      recalculate
+    end
+
+    def add_child(container)
+      @children << container
+      @elements << container
+
+      recalculate
+    end
+
+    def add(element)
+      @elements << element
+
+      recalculate
+    end
+
     def draw
-      Gosu.clip_to(x, y, width, height) do
+      Gosu.clip_to(@x, @y, @width, @height) do
+        raise "width and height are 0!" if @width == 0 && @height == 0 && Gosu.milliseconds > 1500 && @elements.size > 0
         background
 
         Gosu.translate(scroll_x, scroll_y) do
@@ -68,7 +86,6 @@ module CyberarmEngine
           when Gosu::MsWheelUp
             @scroll_y+=@scroll_speed
             @scroll_y = 0 if @scroll_y > 0
-            @elements.each {|e| e.set_offset(@scroll_x, @scroll_y) if e.is_a?(Button) }
           when Gosu::MsWheelDown
             @scroll_y-=@scroll_speed
             if $window.height-@internal_height-y > 0
@@ -76,8 +93,6 @@ module CyberarmEngine
             else
               @scroll_y = @height-@internal_height if @scroll_y <= @height-@internal_height
             end
-
-            @elements.each {|e| e.set_offset(@scroll_x, @scroll_y) if e.is_a?(Button) }
           end
         end
       end
@@ -85,32 +100,58 @@ module CyberarmEngine
       @elements.each {|e| if defined?(e.button_up); e.button_up(id); end}
     end
 
+    def theme
+      @theme
+    end
+
+    def stroke(color)
+      @theme[:stroke] = color
+    end
+
+    def fill(color)
+      @theme[:fill] = color
+    end
+
     def background
       Gosu.draw_rect(@x, @y, @width, @height, @background_color, @z)
     end
 
     def recalculate
       raise "mode was not defined!" unless @mode
-      @packing_x = @x
-      @packing_y = @y
+      # puts "<#{self.class}:#{self.object_id}> X: #{@x}, Y: #{@y}, width: #{@width}, height: #{@height} (children: #{@children.count}, parents: #{@parent&.children&.count})"
+
+      @packing_x = 0
+      @packing_y = 0
+
+      @width = 0
+      @height= 0
 
       @elements.each do |element|
         flow(element)  if @mode == :flow
         stack(element) if @mode == :stack
+
+        case @mode
+        when :flow
+          @width += element.width
+          @height = element.height if element.height > @height
+        when :stack
+          @height += element.height
+          @width = element.width if element.width > @width
+        end
       end
     end
 
     def flow(element)
-      element.x = @x + @packing_x
-      element.y = @y
+      element.x = @packing_x
+      element.y = 0
       element.recalculate
 
       @packing_x += element.width + 1
     end
 
     def stack(element)
-      element.x = @x
-      element.y = @y + @packing_y
+      element.x = 0
+      element.y = @packing_y
       element.recalculate
 
       @packing_y += element.height + 1
diff --git a/lib/cyberarm_engine/ui/dsl.rb b/lib/cyberarm_engine/ui/dsl.rb
index b3648e1..a018536 100644
--- a/lib/cyberarm_engine/ui/dsl.rb
+++ b/lib/cyberarm_engine/ui/dsl.rb
@@ -2,60 +2,72 @@ module CyberarmEngine
   module DSL
     def flow(options = {}, &block)
       puts "Flow"
-      options[:parent] = self
-      _flow = Flow.new(options, block)
+      options[:parent] = @containers.last
+      _container = Flow.new(options, block)
+      @containers << _container
+      _container.build
+      options[:parent].add_child(_container)
+      @containers.pop
 
-      @active_container = _flow
-      @game_objects << _flow
-
-      return _flow
+      return _container
     end
 
     def stack(options = {}, &block)
       puts "Stack"
-      options[:parent] = self
-      _stack = Stack.new(options, block)
+      options[:parent] = @containers.last
+      _container = Stack.new(options, block)
+      @containers << _container
+      _container.build
+      options[:parent].add_child(_container)
+      @containers.pop
 
-      @active_container = _stack
-      @game_objects << _stack
-
-      return _stack
+      return _container
     end
 
-    def label(text, options = {})
-      options[:parent] = @active_container
-      _text = Label.new(text, options)
-      @active_container.elements << _text
+    def label(text, options = {}, &block)
+      options[:parent] = @containers.last
+      _element = Label.new(text, options, block)
+      @containers.last.add(_element)
 
-      return _text
+      return _element
     end
 
     def button(text, options = {}, &block)
-      options[:parent] = @active_container
-      _button = Button.new(text, options, block) { if block.is_a?(Proc); block.call; end }
-      @active_container.elements << _button
+      options[:parent] = @containers.last
+      _element = Button.new(text, options, block) { if block.is_a?(Proc); block.call; end }
+      @containers.last.add(_element)
 
-      return _button
+      return _element
     end
 
     def edit_line(text, options = {}, &block)
-      options[:parent] = @active_container
-      _edit_line = EditLine.new(text, options, block)
-      @active_container.elements << _edit_line
+      options[:parent] = @containers.last
+      _element = EditLine.new(text, options, block)
+      @containers.last.add(_element)
 
-      return _edit_line
+      return _element
     end
 
     def check_box(options = {}, &block)
-      options[:parent] = @active_container
-      _check_box = CheckBox.new(options, block)
-      @active_container.elements << _check_box
+      options[:parent] = @containers.last
+      _element = CheckBox.new(options, block)
+      @containers.last.add(_element)
 
-      return _check_box
+      return _element
     end
 
     def background(color = Gosu::Color::NONE)
-      @active_container.background_color = color
+      @containers.last.background_color = color
+    end
+
+    # Foreground color, e.g. Text
+    def stroke(color)
+      @containers.last.stroke(color)
+    end
+
+    # Element background color
+    def fill(color)
+      @containers.last.fill(color)
     end
   end
 end
\ No newline at end of file
diff --git a/lib/cyberarm_engine/ui/element.rb b/lib/cyberarm_engine/ui/element.rb
index df200f8..d9f3b06 100644
--- a/lib/cyberarm_engine/ui/element.rb
+++ b/lib/cyberarm_engine/ui/element.rb
@@ -13,33 +13,32 @@ module CyberarmEngine
       stroke:     Gosu::Color::WHITE,
       fill:       Gosu::Color::NONE,
       background: Gosu::Color.rgb(12,12,12),
+      checkmark: "X", # ✓
 
       padding: 20,
       margin:   0,
 
       interactive_stroke:            Gosu::Color::WHITE,
-      interactive_active_stroke:     Gosu::Color::BLACK,
+      interactive_active_stroke:     Gosu::Color::GRAY,
 
       interactive_background:        Gosu::Color::GRAY,
       interactive_hover_background:  Gosu::Color.rgb(100, 100, 100),
       interactive_active_background: Gosu::Color.rgb(50, 50, 50),
+      interactive_border_size: 1,
 
       text_size: 22,
       text_shadow: true,
       font: "Consolas"
     }
 
-    attr_accessor :x, :y, :z
-    attr_accessor :offset_x, :offset_y
+    attr_accessor :x, :y, :z, :width, :height, :padding, :margin
 
     def initialize(options = {}, block = nil)
-      options = (THEME).merge(DEFAULTS).merge(options)
+      @parent = options[:parent] # parent Container (i.e. flow/stack)
+      options = (THEME).merge(DEFAULTS).merge(@parent.theme).merge(options)
       @options = options
       @block = block
 
-      @offset_x = 0
-      @offset_y = 0
-
       @x = options[:x]
       @y = options[:y]
       @z = options[:z]
@@ -49,8 +48,6 @@ module CyberarmEngine
 
       @padding = options[:padding]
       @margin  = options[:margin]
-
-      @parent = options[:parent]
     end
 
     def draw
@@ -66,8 +63,8 @@ module CyberarmEngine
     end
 
     def mouse_over?
-      if $window.mouse_x.between?(@x + @offset_x, @x + @offset_x + width)
-        if $window.mouse_y.between?(@y + @offset_y, @y + @offset_y + height)
+      if $window.mouse_x.between?(relative_x, relative_x + width)
+        if $window.mouse_y.between?(relative_y, relative_y + height)
           true
         end
       end
@@ -81,11 +78,20 @@ module CyberarmEngine
       @height + (@padding * 2)
     end
 
+    def relative_x
+      @parent.x + @parent.scroll_x + @x
+    end
+
+    def relative_y
+      @parent.y + @parent.scroll_y + @y
+    end
+
     def recalculate
+      raise "#{self.class}#recalculate was not overridden!"
     end
 
     def value
-      raise "#{self.klass}#value was not overridden!"
+      raise "#{self.class}#value was not overridden!"
     end
   end
 end
\ No newline at end of file
diff --git a/lib/cyberarm_engine/ui/label.rb b/lib/cyberarm_engine/ui/label.rb
index 65f43a9..1fc128c 100644
--- a/lib/cyberarm_engine/ui/label.rb
+++ b/lib/cyberarm_engine/ui/label.rb
@@ -9,18 +9,31 @@ module CyberarmEngine
     end
 
     def draw
-      $window.draw_rect(@x, @y, width, height, @options[:fill], @z+1)
+      $window.draw_rect(relative_x, relative_y, width, height, @options[:fill], @z+1)
 
       @text.draw
     end
 
+    def button_up(id)
+      case id
+      when Gosu::MsLeft
+        if mouse_over?
+          @block.call(self) if @block
+        end
+      end
+    end
+
     def recalculate
       @width = @text.width
       @height= @text.height
 
-      @text.x = @x + @padding
-      @text.y = @y + @padding
+      @text.x = relative_x + @padding
+      @text.y = relative_y + @padding
       @text.z = @z + 3
     end
+
+    def value
+      @text.text
+    end
   end
 end
\ No newline at end of file