Incorrect work of converter

It works ok, but just look at this screenshots, there to small space to enter the numbers. How to fix this? (tried to use both versions of plugin, old and new)

Sidebar: https://prntscr.com/ixxvjm
Main page: https://prntscr.com/ixxvu3

And by the way, how to put it in the center of the page?
https://prntscr.com/ixxwf4

The page I need help with: [log in to see the link]