next js className haven't been set

I've just started playing with next js. so I want to use css as module and setup classname for nav, but in rendered DOM this classname doesn't exist. I can see generated styles by webpack in "head" tag, but I dont see classname on my nav tag.

import React from "react";
import styles from './NavigationContainer.module.scss';

type Props = {};

const NavigationContainer: React.FC<Props> = ({children}) => {
    return <nav className={styles.mainNavigationContainer}>{children}</nav>
};

export default NavigationContainer;