http://kevinshoffner.com/wordpress/tipstricks/custom-css-gravity-forms/
Here is a quick list of all of the built-in classes:
Checkboxes and Lists Fields
gf_list_2col= 2 columned List
gf_list_3col= 3 columned List
gf_list_4col= 4 columned
gf_list_5col= 5 columned
Two Columns of Text Fields side by side
gf_left_half= The left column
gf_right_half= The right column
Three Columns side by side
gf_left_third= Left column
gf_middle_third= Middle column
gf_right_third= Right column
Some other miscellaneous styles
gf_scroll_text= Gets a scroll box into place, for those long sections where you need to give your visitor lots of information
gf_hide_ampm= If you want to hide the AM/PM portion of the Time field
gf_list_inline= Simpliar to the above gf_list classes, but just show up next to each other using the amount of space the content can use on each line, instead of making it fit within 2,3,4,5 columns.
gf_hide_charleft= Do not display the amount of characters left / character counter
I’ve not found a great use for these, but they are available:
gf_list_height_25= 25 pixels between list items
gf_list_height_50= 50 pixels between list items
gf_list_height_75= 75 pixels between list items
gf_list_height_100= 100 pixels between list items
gf_list_height_125= 125 pixels between list items
gf_list_height_150= 150 pixels between list items
