Use this if you would like to have a unique default CSS profile for a specific host (otherwise the sheet is based on the protocol the host is configured for -- see TN3270CSS, TN5250CSS and TNVTCSS ).
When this is set, when a client browser session first connects to the host, the CSS will be set--if the user then changes the selection (if enabled), from then on, the selected CSS profile will be used for the specified host for the client.
Example:
<add key="cssForInsure" value="SC3270Clr.css" />
This will set the default CSS style sheet to SC3270Clr.css for the host named Insure