[O] orgmode header issue with emacs themes

[Isaac]

Hello,

I am cycling my emacs themes (through out the day) to adapt
my eyes' contrast/tiredness during the day. 

However, as I cycled through themes, many times over the dark
color themes, there's an addition for font background -
especially for those 'org-mode' header lines (and comment lines),
which is annoying.

some suggestions to fix this behavior (I am just thinking delete
                                         those org related lines
                                         in the themes for
                                         now)?

thanks a lot

isaac