In the CSS I see Green and Red for buy/sell orders in the tables and for the buttons.
But this does not reflect on the front end regardless the theme I am using.
How can we force the css of the plugin to override the theme’s so the colors are displayed correctly?
In the Exchange’s CSS rules there is nothing giving color to orders and/or buttons. There are some colorings for the chart’s candlesticks, and there are also the red/green rules for markets that had a 24hour increase or decrease in price.
Can you describe what type of coloring you would like to implement? It is possible that I will need to add more classes to the markup for you to apply semantic coloring to table rows.
If you have determined that you need some CSS rule that is not in the plugin, the correct way to add it is to create a child theme to your theme, then add any rules there.