Customize Apache2 directory list

[Jim]

I have a rapsberry pi as a server that among other things holds my music 
collection.   Today I got Apache2 running on it to serve music to my 
android phone so could listen when I'm out in the yard.   It works but 
the size of the text in the directory listing is really small.  How can 
I enlarge the size of the text?    I looked online but didn't find 
anything that  made sense.  Some sites said to use a css file.  One site 
even included an example css file.  However nobody shows how to use it.  
My understanding of css files is they affect how stuff is displayed in 
an html page.  When I get a directory listing, it doesn't display an 
html page.  It shows me what's in the directory.


Help please and thanks.