@Durangod, Loads of thanks, that you have tried it and tried to help me. I am aware of the css refresh stuffs... I have checked editing the default css, it works for other places that use two_column_left_sidebar_maincontent, only except the area used to type the blog. (it is similar place like this one, where I am writing to you!)

Any other clue?

Thanks again...

Wait a sec, look at the bottom of *this* page, where we type our comments, there is a line "Post a comment" or a button "save" etc. Now in *this page* this color is WHITE, right?  If you change the color of two_column_left_sidebar_maincontent in the selected theme, this color (WHITE in *this page* for example ) will change for blogs viewing...but if you try to write one this becomes blue. OH one more clue for your research, I have changed the border color in two_column_left_sidebar_maincontent, and it has effect as expected!

By *this* I meant the text area of this page you are currently viewing... 

http://community.elgg.org/mod/groups/topicposts.php?topic=431375&group_guid=23300

:) Thanks much!

@ Nasim, the blog edit is not under the two_column_left_sidebar_maincontent div. its using another layout called two_column_left_sidebar_edit or some thing called blog_edit_page. its css is available in blogs/views/default/blogs/css.php. you need to make changes there.

Loads of thanks to Durangod and Team Webgali.

Yes, the code is there in blogs/vies/default/blogs/css.php as you mentioned.

#blog_edit_page #two_column_left_sidebar_maincontent {

margin:0 0px 20px 20px;

padding:10px 20px 20px 20px;

width:670px;

background: red;  //#bbdaf7;  // << Here I am playing with red... 

}