Adding custom CSS style to table values on Gateway

Can someone tell me how can I add a custom CSS style to the values in RecordActionTable on the gateway for example as seen on image below (Status column). I tried with adding html tags but they don’t work (they are displayed like string). Thank you for your help.
[attachment=0]status.png[/attachment]

Try overriding the implementation of .getCalculatedFieldDisplayValue(). That method accepts whatever object you return from your calculated field’s getFieldValue() method and converts to a string. By default, it takes any Collection and turns it into an HTML bullet list, and runs anything else through String.escapeMarkup(). If all of your calculated fields handle markup themselves, you can pass those results straight through your own .getCalculatedFieldDisplayValue().