can we customize the styles of the npm packages after installing in our react project according to our needs like changing colors etc.

I’ve installed a npm package which is “rc-slider” in my react project. Now, i wanna customise those sliders like colors and size according to my project needs. first i inspect those element and found their selectors classname after that in node modules directory there is rc-slider/assets/index.css. I tried changing the color and size of sliders but still changes are not reflecting in web page.
Help me!