I want a beautiful sidebar UI like the one shown in their screenshot here:

https://www.npmjs.com/package/react-pro-sidebar

Their demo also shows its usage. However, just using it like this creates a very ugly sidebar. I thought it would look good by default.

<Sidebar>
  <Menu>
    <SubMenu label="Charts">
      <MenuItem> Pie charts </MenuItem>
      <MenuItem> Line charts </MenuItem>
    </SubMenu>
    <MenuItem> Documentation </MenuItem>
    <MenuItem> Calendar </MenuItem>
  </Menu>
</Sidebar>;

Where do I get the code that replicates the sidebar shown in their screenshot?