XessLite is configured using X resources (see the X(3)
man
page for more information about X resources). The default resources
for XessLite are found in the Xslite4
app-defaults file,
usually installed in the /usr/X11R6/lib/app-defaults/
directory. If you wish to modify the default resources, we recommend
copying this file to your home directory and modifying it there instead
of modifying the system-wide app-defaults file.