anyone idea how to add custom CSS file to SharePoint 2016.
"<SharePoint:CssRegistration ID="CssRegistration2" Name="/Style Library/css/customized.css" runat="server" After="corev15.css" />" not working.
Thanks a lot
Regardless what's the way that you are using, but the following steps should be working in SharePoint 2016
At Alternate CSS URL >
Specify a CSS file to be used by this site and all sites that inherit from it: > Browse your file.
Reset all subsites to inherit this alternate CSS URL if you need to apply this for all Subsite.
After I updated your question, you were missing the format of code. so I found out you are using
SharePoint:CssRegistration , So try to use it as the following
<SharePoint:CssRegistration name="<% $SPUrl:~sitecollection/_catalogs/masterpage/css/customized.css %>" runat="server" />
<SharePoint:CssRegistration ID="CssRegistration1" name="<% $SPUrl:~sitecollection/_catalogs/masterpage/css/customized.css %>" runat="server" after="SharepointCssFile" />
For more details check Starter Master Pages for SharePoint 2016