Theme switching to default style.css

[Fistfull]

New to this, so please bear with me if this is obvious as the blue sky 
Installed theme Aquamania Dark Blue01 (Thanks Andrea  ) Looks awesome, just what I was looking for.  When I go to the messages the theme is reverting to the default "style.css", what is the code I need to change, to make (guessing here) "Messageindex.template.php" use "/themes/amdblue01/style.css" instead of /themes/default/style.css?   

Thanks
Rick