Add shoadow to valid section.

Move shadow from navigation to all header.
Merge pull request #46 from vash000/layout-fixes

Add shadow to valid section.
Set none decoration for element link a
Merge branch 'link-a' into alpha
Create code club section slides
Merge pull request #48 from pgle/teach

Create code club section slides
Add close button for section slides
Merge pull request #49 from pgle/teach

Add close button for section slides
added animation in Why section
Merge pull request #50 from mjasion/feature/whySectionAnimation

Add animation in Why section
Create workshops section
Merge pull request #51 from mkiedys/pt

Add workshops section
Create why section
Merge pull request #52 from pgle/why

Create why section
Merge remote-tracking branch 'upstream/alpha' into alpha