style - Building Expressions for QGIS Markers

I have a tab delimited text file with a column "Status". It can have values OFF-AIR or ON-AIR. How do I control the marker properties like colour or out-line using the expression building. I am not looking for categorized symbol, I need the expression. This is my syntax, but it is not working:

CASE WHEN  "STATUS"  = 'ON AIR' THEN  color_rgba(255,255,0,80)
  WHEN  "STATUS"  = 'OFF AIR' THEN  color_rgba(255,0,0,80)

END

Answer

Haven't come across this issue before but it seems to work if you use three single quotation marks for the values:

CASE WHEN "STATUS" = '''ON AIR''' THEN color_rgba(255,255,0,80) 
WHEN "STATUS" = '''OFF AIR''' THEN color_rgba(255,0,0,80) 
END