How to add custom CSS to SP2010 site?

FYI, to avoid an issue with Ribbon loosing the focus aftert adding Webpart to a standard list view page - AllItems.aspx as example, use the following method instead of adding CEWP CSS code.

http://fitandfinish.ironworks.com/2010/01/the-best-way-to-add-custom-css-to-sharepoint.html 


As example I wanted to avoid file name wrapping (if it contains spaces) and I added stype definition in CEWP


<style type="text/css"> .ms-vh { WHITE-SPACE: pre } .ms-vh2-nofilter { WHITE-SPACE: pre } .ms-vh2-nograd { WHITE-SPACE: pre } .ms-vh2 { WHITE-SPACE: pre } .ms-vb { WHITE-SPACE: pre }</style> ,
but then user will have to select list webpart in order to see tabs Documents and Library. So we would add it into header instead.

<asp:content contentplaceholderid="PlaceHolderAdditionalPageHead" runat="server"> <link href="/sites/client/Style%20Library/client.css" rel="stylesheet" type="text/css" /> <SharePoint:RssLink runat="server"/> </asp:content>