column Header of Integer type field is not aligned center but other Char type fields aligned correctly, my css file contains:

.center_class table > thead > tr > th {
text-align: center;
}

and in xml file : tree string="Patients" class="center_class"

all column Headers are centered correctly, (it means i have added css file correctly in manifest file) but an Integer type is still on right side. 

i am asking for column Header's alignment. 

please help.

regards