The new Release 20.03 is out! You can download binaries for Windows and many major Linux distros here .
You can not change the color of the UI (toolbars, status bar and so on) Codeblocks uses the system default theme.You can change the colors of the editor:http://wiki.codeblocks.org/index.php/Syntax_highlighting_custom_colour_themes
I don't know what you mean. Can you describe more?You can change the coloring of the code in Settings->Editor->Syntax highlighting->Colour themeI don't know if there is a default dark theme. I imported mine from the wikiMany colors can also be changed in Settings->Environment->Colours.I have to admit that this is all a mess....[Edit:] There is a installation instruction on the bottom: http://wiki.codeblocks.org/index.php/Syntax_highlighting_custom_colour_themes#Installation