It works for sure.
Maybe you point to the wrong path? Where is "css" folder location. If in the web content root, use "/css/basic.css"
Other possible problem is overriding what you declare in the basic.css by classes declared latter (inserted latter in the head section). It is possible if you try to override style of components
Sergey thank you for quick response.
It seems to be my mistake. forgot to put <f:view> tag. That's what working for 12 hours means. :)