Why are the fields in the grid red/green/blue?

When a field is history-tracked in Salesforce, Clari includes highlights fields to indicate that a change to that field has been made recently.

Note: Clari only highlights fields that are history tracked on the Opportunity Record in Salesforce. If a field on the Account Object is history tracked in Salesforce, Clari will not highlight those fields in the Opportunity Grid.
 

You can define what "recently" means — the default timeframe is 7 days, but you can be adjust this by clicking Edit View in the upper-right of the grid.
 

Here's what each color means

Green: indicates a positive change (i.e. Deal Size increased, Close Date pulled in, progression from Stage 3 to Stage 4, Forecast Category updated from Best Case to Commit, etc.)

Red: indicates a negative change (i.e. Deal Size decreased, Close Date pushed out, regression from Stage 4 to Stage 3, Forecast Category updated from Commit to Best Case, etc.)

Blue: indicates a neutral change (i.e. Next Steps updated Reseller changed, etc.)