edit your skins _main.php

search is your friend:

http://forums.b2evolution.net/viewtopic.php?t=3270&highlight=sidebar
http://forums.b2evolution.net/viewtopic.php?t=2749&highlight=remove+sidebar
http://forums.b2evolution.net/viewtopic.php?t=2561&highlight=remove+sidebar

iFrames?! ARGGHHH!!!

*runs and hides from the horrible iframes* ;)

yeah you are right whoo, i have find how to do it my self some minutes after.
and i searched before posting but i didn't find anything, sorry.

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i would also like to know how to change the login background color from white do another one, i have tryied 9999 things and didn't found how to do it, can anyone help me here?

It's a different style sheet for the login pages. I forget off the top of my head what it is, but it's in the admin folder. I'm pretty sure. Wait a sec... Yeah. Look in admin for legacy and desert and variation dot css. Personally every time I play in that sandbox things get broken really bad, but that's just me.

EdB i already know is something in those CSS i think it's in the desert one but there's so many things in there :s if anyone knew wich one it would be great, i'll keep searching.

but thanks =)

edit: i have tryed all the styles in those 3 CSS in the main folder and none changed the background of the login/register page, i really need this so if anyone has an idea tell me,

thanks in advance

/**
 * Backoffice main Cascading Style Sheets definitions
 *
 * b2evolution - {@link http://b2evolution.net/}
 * Released under GNU GPL License - {@link http://b2evolution.net/about/license.html}
 * @copyright (c)2003-2004 by Francois PLANQUE - {@link http://fplanque.net/}
 *
 * @package admin
 */
 
@import url(../rsc/basic.css);	/* Import basic styles */
@import url(../rsc/img.css);	/* Import standard image styles */
@import url(../rsc/blog_elements.css);	/* Import standard blog elements styles */
@import url(../rsc/forms.css);	/* Import default form styles */
@import url(../rsc/comments.css);	/* Import default comment styles */

body {
	margin: 0;
	background-color: #FF0000;
	color: #000;
	font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;
	font-size: 84%;
}

This was from admin/desert.css and produces a red background on the login page. Originally background-color was #fff.

Got link to your login page?

i already tryed that EdB and it doesn't work, have you tryed it? if you did it's me that just distroyed the blog :s
i don't have it online yet sorry

Yes I did, and no problems (other than an ugly red background...). I tested it on a basically stock v11 installation using the developers toolbar in Mozilla, and only to see if it would affect the background color in the way you want.

GOT LINK?

Since the obvious answer isn't working showing where the problem is can help people help you. Like for example viewing your source and applying the developers tool bar to your page.

EDIT: OOPS! My Bad! I see where you say you don't have it online yet. That makes linking kinda tough...

Have you tweaked the css deeply? Can you test with an unadulterated skin?