show categories hierarchical

[junyoungpark92]

Hi, thank you for making this theme.
It's so cool, but I have two question for this.

First question

I already configured categories, but it seems like that doesn't support sub directories.
I have sub directory(category) for my post, like

linux/about-linux.md
linux/ubuntu/about-ubuntu.md
linux/centos/about-centos.md

I even have 3-depth category as well.
It's not supported?
If it's not supported, I wanna watch some code about this feature.
Could you tell me where code it is?

Second question

After configure categories, I can see that _draft directory also in categories pages.
I don't wanna expose this directroy. Is there any way to do this?
If it's not support, I'm gonna appreciate you to tell me where code is.

Thank you.