In this question you're asking about the "rowClass" param of the Sideview Table module, and for those following along this question came from a comment on this other question - http://splunk-base.splunk.com/answers/60993/colorize-simpleresultstable-rows-based-on-field-values.
The value of the Table module's rowClass param, as calculated at runtime can contain spaces, whether or not those spaces come from the dynamic field value(s) present by virtue of $fieldName$, or from hardcoded parts of the string. However in CSS a space in there means that multiple classes are being applied indepently to the element. EG: if the rowClass value were "informational 1", then you'd be applying two classes independently, "informational", and "1". Each of those classes you'd have to define in your stylesheet, and needless to say "1" is a very strange classname to use.
To simplify this, I would stay away from spaces in the fieldnames that you're using in rowClass. Specifically I would use | eval myClassField=replace(myClassField," ","_") either in the base search or in a postProcess search, to turn those values into "informational_1", "informational_2", etc.. That will mean they act as a single class and you can define those informational_1, informational_2, informational_3 in your CSS.
