Fix Koa Example

[cblanquera]

What version of Reactus are you using?

0.6.5

What OS are you experiencing this issue?

OSX

Describe the Bug

Koa example style is not centered. Button is not working

Expected Behavior

Koa example page to be consistent with the other examples.

To Reproduce

Run yarn koa dev visit http://localhost:3000 try to click the button.

Include git repo/fork so we can easily reproduce the issue

No response