Conditional Formatting-How to classify unread records inside Crm

HI,

I have a requirement for classify unread record inside Crm 2015.

Example:

We require some colour change in opportunities view  data which are not open by assign sales person,if manager create opportunity and assign to sales person 'A' then subject record would shows in red colour until it is open by  sales person 'A'.We are not using outlook so please don't give me outlook Conditional Formatting solution.

Danish