why nav btn takes automatic color in ract js code example

Example: move navbar items to right with reactbootstrap

<Navbar bg="light" variant="light">
            <Container>
                <LinkContainer to="/">
                    <Navbar.Brand>Navbar</Navbar.Brand>

                </LinkContainer>
               // <Nav className="mr-auto"> to  <Nav className="ml-auto">
                    <Nav.Link to="/cart">Cart</Nav.Link>
                    <Nav.Link to="/login">Sign In</Nav.Link>
                </Nav>

            </Container>
        </Navbar>
// just change the margin-right(mr-auto) to margin-left(ml-auto)
// This should be working fine