any idea to increase font size ?

[aish_varya]

my custom fonts looks perfect but when reading sms n writing its really hard to read.
i just want to increase sms text size rest all is fine. or may be if changing fonts for jus the sms text.
i dont know either of above things

i have searched alot, it has modifications with the layout.xml file for the the fonts to increase and to change font. but i was unable to set those changes to the layout file. can anybody tell how do i specify sperate font for SMS reading and writing or increasing font size while reading n writing sms
im waiting