add custom html in record view

I want to append new custom html section on opportunity record view to display dynamically amount with specific color. For ex:In opportunity,

1. If linked RLI total is Rs.20000/- then it displayed on red background div with 20X20 pxl but its fully responsive.

2. If linked RLI total is Rs. 50000/- then it displayed on green background div with 20X20 pxl yes its also fully responsiv.

anyone can help me to figure it out or find the proper solution.