how to change height of header in customer portal of otrs

[keerthi]

hi,

i wan to increase the header height in otrs customer portal, can any one help me i got options for changing logo and header name but how to change the height of the headerbar.
Thank you..

[keerthi]

nobody????

I think i need to change .css file, but i dont know which .css file i need to modify...
can anyone help me.....