ATTENTION AN EDIT HAS BEEN ADDED.
Hi mapper guys and gals,
if you have problem with mapping,
and your problem is
"I don't have real Steam CS:S.How can I get all CS:S Textures without Source SDK?"
well, here is you solution. ;D
Hope you donate some good maps here! Say thank you to Lumi!

Edit #1 :
If u have this problem :
I cannot find my grids on my Source SDK Hammer, and I cannot see any of my brush.
All the four viewpoints (camera, top, front, side) show black screen with weird white lines.
//Go to Tools>Options, go to configuration tab, and find Game Executable directory.
//Change it with example D:\Source SDK [the original Source SDK folder, not your CSS folder]
//It worked on me, if problem still stays, just google the problem.It is the common problem.