text-orientation

This property specifies the orientation of the text in relation to the feature the text is representing. This property has an effect on linear features only.

Possible values are:

flow: the text will orient (rotate) itself in the direction of the line. This is the default value.
fixed: the text orientation will be fixed regardless of the line direction.

Example:

text-orientation: text

specifies that the text will be displayed horizontally on the line.