reactjs sidemenu style missing

Question

I'm new to reactjs and tried to use the sidemenu from reactjs (https://www.npmjs.com/package/react-sidemenu). I installed it via npm and made a component:

  render() {
    return (
        <div>
            <SideMenu>
                <Item divider={true} label="Segment 1" value="segment1" />
                <Item label="Item 1" icon="fa-search">
                    <Item label="Item 1.1" value="item1.1" icon="fa-snapchat">
                        <Item label="Item 1.1.1" value="item1.1.1" icon="fa-anchor" />
                        <Item label="Item 1.1.2" value="item1.1.2" icon="fa-bar-chart" />
                    </Item>
                    <Item label="Item 1.2" value="item1.2" />
                </Item>
                <Item label="Item 2" value="item2" icon="fa-automobile">
                    <Item label="Item 2.1" value="item2.1.1">
                        <Item label="Item 2.1.1" value="item2.1.1" />
                        <Item label="Item 2.1.2" value="item2.1.2" />
                    </Item>
                    <Item label="Item 2.2" value="item2.2" />
                </Item>
                <Item divider={true} label="Segment 2" value="segment2" />
                    <Item label="Item 3" value="item3" icon="fa-beer" />
                </SideMenu>
            </div>
        );
    }
}

I also installed FontAwesome but they style is completly missing. I only see a list of the items without any style.