> I changed the font size in .vimrc, but why it does not work in vim
> files? instead, it works in gvim files?
Vim is the "console" version, it uses whatever font is handed to it by
the video terminal (or terminal emulator) in which it is running.
When running in a Windows "Dos Box", to change Vim's font size, click
the "V" icon at the left end of the titlebar (or hit Alt-Space or use
":simalt ~" without the quotes), then "Properties", then use the "Font"
tab, change anything you want there, and finally "OK".
I suppose there are similar procedures for Linux, Mac, et al., but I'm
on Windows at the moment.