To track changes at the field level requires script triggers and scripting. The OnObjectModify and/or OnObjectSave triggers would be needed to perform scripts that capture the name of the field, the ID of the record and log either the new value or (more easily) log the original value of the field in a related table.
Conditional formatting expressions could, in theory access the data in this table in order to apply a conditional format. ExecuteSQL might be particularly handy in serving as a way to access the specific change record for the correct record and field.
HelperField [formula; timestamp] =
YourFieldToWatch = YourFieldToWatch; get(SystemTimeStamp);
// other fields to be added...
there are also custom functions by Ray Cologon (SuperLog,UltraLog - one of both is payware AFIK)