[Feature Request] More width option, TOC support

[menduo]

Dear devloper:

Thanks for the great app. I have to feature request below:

More width option

Here are three width now:

1. default;
2. wide screen;
3. full screen ( close sidebar )

It will be great that you can add the fourth option: between "default" and "wide screen", that will be good for some conversation.

TOC support

In some conversations, I have asked too many questions, it will be very easy to navigate to any question if there be an TOC on the right side.

Thank you.