What is the Proper Syntax for an Exception Report Using the IF Argument

Summary: Looking to change the color of the text when a result is outside of a SLA Using an Exception Report With a Logical Test

Content (required):

The report I've written will show the Elapsed time of a Performance interval for each Incident, in seconds. There are three SLAs being tracked in one report. Using the Exception Report Wizard is not working for me. I need to write an expression such as:

IF(date_diff(inc_performance.time_end, inc_performance.time_start) > 1800 & incidents.severity_id = 1, Change the color of the text to red, Else use the default text color))