There are three css files in your not-styled-like-my-theme page and none of them are coming from the writr theme.
The goal you want is to get the writr theme’s css on that page.
Unfortunately, I did this in Google Chrome and the results are probably not what you’re looking for.
This means your page and theme appear to be incompatible, unless that is indeed what you want. In which case, in the Appearance->Editor, you could find the file that your not-styled-like-my-theme page is and add a few lines in the header for the css file from your theme.