Conditional formatting allows you to create several conditional formats for one column within your data source.
Here is a step by step guide on how to create conditional formatting within your chart.
Go to your data tab> select conditional format> select Add new set of formats
Enter the name of the condition> click ok
Select Add new format> manage rules
New Rule> add criteria
Add the criteria that you want to base your conditional formatting off of> click ok> click ok again
Another box will pop up so you can put the formatting to your field> select font style
Select the font style you want to apply as well as either the fill style for the letters or the background color for the field> click ok> click ok
Click ok to apply the formatting to the chart.
Conditional Formatting Apply to your chart