Moving bcha page CSS to main.css
The override.css file was not the ideal place to put the CSS for the new bcha page. Was not rendering live.
Moved the new rules to main.css instead
Test Plan: Make sure page is rendering properly live
Reviewers: #bitcoin_abc, jasonbcox
Reviewed By: #bitcoin_abc, jasonbcox
Differential Revision: https://reviews.bitcoinabc.org/D8484