Which files are affected by Index listing editing?

I would like to know which source files (and which lines of them) are affected by setting index listing>>new product columns per row. One told me that changes in the stylesheet files are in terms of percentages. According to him, converting percentages to absolute numbers could make the template more stable. In some country versions of iexplorer I see some stability problems. For instance, two column per row is displayeded as one column per row.
I use zencart v. 1.3.8 wit mistic template.
I appreciate any help

percentage assigned to width of additional images are not set in CSS , but they are created through ZC core logic . to identify any files , code, text , variable , etc.. i suggest you to use Firefox browser , Install FireBug extension .. using firebug, you can identify corresponding DIV id , or class , and use Developer tool kit in your admin to look for core files that contain those items.

however, if IE browser shows single column rather multiple column then there is something wrong with CSS. and how IE renders or understands your CSS. and that has nothing to do with , width value assigned to your Additional images DIV .

Tony_sar,
Thank you for the answer which has clarified the issue.
As a beginner, this clarification conceptually helped me but I am still unable to correct the relevant css codes.
I appreciate further if you look at my relevant post on this matter and express your opinion. Thanks.
(post below is copied from the thread http://www.zen-cart.com/forum/showthread.php?t=126332 )

*Steve,

I have one more question.

The problem above have been solved for most browsers.

Using firefox I get two images per row
( http://193.140.141.18/~akaraman/ct3.jpg ), which is what I want.

At local versions of internet Explorer the problem stil exists
( http://193.140.141.18/~akaraman/ct2.jpg ); however a forum member having an American version of ie reports that he sees two images per row.

Is there any simple trick to make it sure that it displays two images per row at every browser?

I have been searching an answer for a long time; I appreciate any help.

ps. The website under consideration is http://www.camtasarim.com/

add this to your stylesheet.css

#whatsNew {
display:inline;
float:left;
}

display:inline needed to fix the problem with IE . but for some reason it effects the border .at least from my end is effecting right border on IE.

Tony_sar
Thank you.
I added your codes to the stylesheet.css file with a little change. By trial end error, replacing "left" by "center" it became:

#whatsNew {
display:inline;
float:center;
}

Now, in terms of images per row, it has the same performance at both the firefox and the internet explorer.
Thank you very much!

just for your correction . there is no Center value for Float.. so
float:center will cause validation error.