To edit the texts colour download NSE classic version.
Open your ROM and do this:
Goto "Options"=>"Bookmarks"=>"View Bookmarks", Then should a new box appear with a row of things on the left where you see a "+" before the things, or looking like this"
+Textboxes
+Backsprites
+Backsprites etc.
Click on the "+" at textboxes and there should appear new stuff(Type1, type2,type3 etc).
click on "Type1", then should appear right the textbox, click "Open" and close that little window (KEEP NSE OPEN).
Then do this please:
Goto "Edit"=>"Palette".
After this open a new window that has a palette, if you change the correspondending colours the text ingame will change.
You wanted to change the shadow of the text so change the 4th colour(5a67) in that window to the colour you want.