make sure mark as unread css is working as expected.
```
const menuIconSize = renderStyle === 'chat' ? 24 : 16;
const btnCls = classNames(css.menuContent, {
[css.menuContentVisible]: menuVisible,
});
return (
<div className={css.menu} onMouseLeave={hideMenu}>
<button onClick={toggleMenu}>
<SWMansionIcon icon="menu-vertical" size={menuIconSize} />
</button>
<div>
<button className={btnCls} onClick={toggleUnreadStatus}>
<SWMansionIcon className={css.mailIcon} icon="mail" size={18} />
{toggleUnreadStatusButtonText}
</button>
</div>
</div>
);
}
```
looking at the mark as unread component, all CSS classes moved here are used in the component.