centering a theme - how?

Giselle theme? Did you mean Gillette? If not, post a link to your website or to the theme.

Something like
style="margin:0 auto;"

yes, i meant Gillette
excuse my error

Merged on Sep 24 2012 at 07:51:32:
i just need to know while file and which line i need to change
i can figure out the code, most likely what PolarFox suggested

As what Polarfox said, do make that change in the body section in styles.css file of your theme...

[syntaxhighlighter brush=css,first-line=1,highlight=0,collapse=false,html-script=false] body {
margin: 0;
margin-left:auto;
margin-right:auto;
}[/syntaxhighlighter]

You could try something like that.

i tried both code
nothing

when i coded it to reduce its width
it too was not working
until i added this code to the main site index.php

header("Cache-Control: no-cache, must-revalidate") ;

that was to clear the cache

now back to the issue at hand

i also added the above recommended codes to
.main-body {

but nothing

Just open styles.css and add to body {}(line ~33):
[syntaxhighlighter brush=css,first-line=1,highlight=0,collapse=false,html-script=false]width: 900px;
margin: 0 auto;[/syntaxhighlighter]

Search for this in theme.php
[syntaxhighlighter brush=php,first-line=1,highlight=0,collapse=false,html-script=false]function render_page($license = false) {
global $settings, $main_style, $locale, $mysql_queries_time;
[/syntaxhighlighter]

Change to:
[syntaxhighlighter brush=php,first-line=1,highlight=0,collapse=false,html-script=false]function render_page($license = false) {
global $settings, $main_style, $locale, $mysql_queries_time;
echo "<center>";[/syntaxhighlighter]

Search for:
[syntaxhighlighter brush=php,first-line=1,highlight=0,collapse=false,html-script=false]if (!$license) { echo "<br /><br />\n".showcopyright(); }
echo "</td>\n";
echo "</tr>\n</table>\n";[/syntaxhighlighter]

Change to:
[syntaxhighlighter brush=php,first-line=1,highlight=0,collapse=false,html-script=false]if (!$license) { echo "<br /><br />\n".showcopyright(); }
echo "</td>\n";
echo "</tr>\n</table></center>\n";[/syntaxhighlighter]

All of the code mentioned above, is located under the render_page function. This will allow your page to render as being centered for the Gillette theme.