diff --git a/TODO.md b/TODO.md
index 957e5d4..da8b365 100644
--- a/TODO.md
+++ b/TODO.md
@@ -2,13 +2,9 @@
 
 ## Under development
 
-- Porting for Microsoft Windows and Apple macOS
+- Port for Microsoft Windows
+- Port for Apple macOS
 
 ## Ideas
 
-- empty
-
-## Done
-
-- Randomize PC's moves with same score
-- Fix missing icon in about dialog (the window icon is platform dependent)
+- Migrate to Gtk4 (and maybe Libadwaita)
diff --git a/colors/default b/colors/default
index 783624f..f987ba2 100644
--- a/colors/default
+++ b/colors/default
@@ -5,7 +5,3 @@ bg=#83582d
 fg=#ffffff
 light=#cc9c59
 dark=#6e4b1b
-
-focus-border=#fff
-hover-border=#787878
-possible-move-border=#adaf7c
diff --git a/doc/italian-draughts.5.scd b/doc/italian-draughts.5.scd
index dd2c9ef..09dfc98 100644
--- a/doc/italian-draughts.5.scd
+++ b/doc/italian-draughts.5.scd
@@ -8,25 +8,41 @@ italian-draughts reads the application data from the following path:
 
 - /usr/share/italian-draughts/
 
-## IMAGES
+# THEMES
 
-In the images subdirectory this program reads the following images:
+For each resource type this program first reads from the 'default' file
+located inside the directory of the resource type.
 
-- pcDame.png: PC dame/king
-- pcPawn.png: PC pawn/man
-- plDame.png: Player dame/king
-- plPawn.png: Player pawn/man
+Then, if the user specified a theme, from the file whose name corresponds
+to the theme name. New values can be added or overwrite the default ones.
 
-Note: all images must be the same size
+Every line of a resource file must be a <key>=<value> pair without whitespaces.
+Empty lines or those starting with *#* are ignored.
 
-## THEMES
+## colors
 
-In the themes subdirectory this program first reads from the 'default' file
-and then, if the user specified a theme, from the file whose name corresponds
-to the theme name. New values can be added or overwrite the default ones.
+Used colors are:
 
-Every line of a resource file must be a <key>=<value> pair without whitespaces.
-Empty lines or those starting with # are ignored.
+- border: Chessboard border
+- bg: Backgroud
+- fg: Foregroud (text color)
+- light: Light grid cels
+- dark: Dark grid cels
+
+## images
+
+Images are considered a resource type but every theme is a directory instead of a regular file.
+So for each theme directory there must be an index where every line is the image key
+that is a image filename without extension.
+Every image file is called _key.png_ and there must be the following image keys
+at least in the default theme:
+
+- pcDame: PC dame/king
+- pcPawn: PC pawn/man
+- plDame: Player dame/king
+- plPawn: Player pawn/man
+
+Note: all images must be the same size
 
 # SEE ALSO
 *italian-draughts*(1)
diff --git a/src/README.md b/src/README.md
index e0725df..857f77a 100644
--- a/src/README.md
+++ b/src/README.md
@@ -6,7 +6,7 @@ for creating this program. The structure is described below.
 Note:
 
 - X : Y means X is subclass of Y
-- X::Y means Y, that is declares inside X
+- X::Y means Y, that is declared inside X
 
 ## Frame : wxFrame
 
@@ -18,14 +18,15 @@ A 8x8 grid panel that represents a chessboard.
 
 ## MatchManager
 
-This class handle 1 or more matches using a specific ChessboardGrid
+This class handle matches interacting with a ChessboardGrid
 
 ## GameUtils
 
 This class provides a static method to find all possible moves from a specific
-pieces' disposition.
+pieces' disposition and a static method to calculate the best move the PC
+can make (Minimax algorithm)
 
-### gameUtils::AlgorithmThread : wxThread
+### GameUtils::AlgorithmThread : wxThread
 
 This class provides a simple way to calculate the best move for PC using a
 separate thread that calls the 'calculateBestMove' static method of GameAlgorithm
@@ -38,11 +39,6 @@ It represents a move that can be done by the player or PC.
 
 A class that represents a square in the chessboard.
 
-## GameAlgorithm
-
-This class allows the computer to play against a player providing a static method
-to calculate the best move for PC.
-
 ## Resources
 
 A class the provides the ability to fetch colors from a particular theme.
diff --git a/src/Resources/README.md b/src/Resources/README.md
index 4a2c995..bf37604 100644
--- a/src/Resources/README.md
+++ b/src/Resources/README.md
@@ -18,13 +18,20 @@ Please refer to [wxWidgets wiki](https://docs.wxwidgets.org/3.2.1/overview_i18n.
 
 This program can be started with a specific theme, or it will use the default one.
 
-Assuming the chosen theme is **theme** this program reads from the following path
-in a simple format as described below. If the file does not exist, it is unreadable or
-colors are not available, they fall back to the default ones.
+Assuming the chosen theme is **theme**, for each resource type this program reads from
+the following path in a simple format as described below.
 
-- /etc/italian-draughts/themes/**theme**
+For each entry if the file does not exist, it is unreadable or the entry is not available,
+it fall back to the default one.
+
+- /etc/italian-draughts/**resource_type**/**theme**
 
 ### File format
 
 Each line can start with a "#" to indicate a comment or be a key=value pair divided by a "=" without
 whitespaces of any type.
+
+### Resource types
+
+- colors: UI colors
+- images: Bitmaps in PNG format (keys does not include extension)