i have to get a single page-article website ready.
The website has to look good, and attractive to read the article for 15-20 minutes.
Where can i get some free CSS templates, for my requirement...
Please help.

This website was on the top of the list:

Latest Free CSS Templates

If you do a Google search there are a whole bunch more offering free CSS templates, too many links to provide.

Smart choice going with a CSS template. It is modern, clean, and free. CSS templates I find are so much easier to edit into your own needs as well.

managed... finally... thanks for help...

There are a number of template library websites where you can browse the templates, often view demos of them, and download them if you wish. All for free. Then, you can customize them with your own graphics, logos, etc. as you see best.
In addition to these libraries of free templates, many of the commercial template providers have a few professional quality templates that they give away for free. They want you to sample the quality of their templates as well as making a contribution to the open source community.

one of them:
Deprecated: Assigning the return value of new by reference is deprecated in /home/welcome/public_html/components/com_bookmarks/bookmarks.html.php on line 143

Also, a good alternative to free templates would be make and code a CSS template yourself based off a tutorial. It allows you to change up some things so it does not look exactly like the free template.