Thank's your answer, I read your Themes article but unfortunately it does not write anything about text/background color meaning or about the Sample window of the Theme colors.
I don't have any anomalies in my document, only I want to understand the meaning of text/background Dark1,light1 Dark2,light2 (I know dark1/light1 is the default colors but when used the dark2/light2) namely how to use them and how they look in the "Sample window"?

Thank you in advance.