Hi Absar
I’m using Twenty Eleven too.
As you noted, the Twenty Eleven theme displays the Default page template…too narrow.
There is a Showcase page template that uses the full width, as you discovered however the Showcase page template is designed to show the posts. Our site is like a website, so that Showcase page template works well on the Home page.
If you don’t like that, then that means you can use the Default Page Template and Sidebar Page Template for other pages. Default is too narrow as you noted; Sidebar looks fine.
Default Page Template is nice because you don’t have the sidebars, but why we asked – why so skinny?
Here is the fix for your child theme’s css style sheet to widen the Default Page Template in Twenty Eleven. This fix also corrects the same narrow width problem on a single post page.
Originally the width was set to 68.9%. At 100% everything looks right.
It is a lot of css – I placed the entire section in my css because I may need the other elements later. I only changed the width in the last section.
`
* Singular */
.singular #primary {
margin: 0;
}
.singular #content,
.left-sidebar.singular #content {
margin: 0 7.6%;
position: relative;
width: auto;
}
.singular .entry-header,
.singular .entry-content,
.singular footer.entry-meta,
.singular #comments-title {
margin: 0 auto;
width: 100%;
}
‘
Just in case, I wanted to add – maybe you want to check and be sure to select your child theme instead of Twenty Eleven through the Admin panel as part of placing it into action? That’s what points the system to use your child theme’s css. I’ve got the import trick at the top of mine to bring in all of Twenty Eleven, then this css sits below that to customize my site.