How to override colors on various menu and buttons?

I've that some EasyBlog colors are controlled by the Joomla template UI such as found in 'Global Template Styling' and 'Main Content/Side Content Block Styling'. The problem is when I make some things light/dark for EasyBlog in the global template, it conflicts with other pages. I would like to know if it is possible to change the colors of various items for EasyBlog only: (see screenshot)

1) The background color for the 'Continue Reading' button?
2) The background color for the menu/tool bar for authors (not the main blog page)
3) The button color for the menu/tool bar for authors (not the main blog page)
4 The link text for the menu/tool bar dropdown for authors

I'm using the Joomla Pixel template. I've read in other posts that I need to edit the templates .css file and add some code. While I've looked, I'm not exactly sure which file that is. Can I use the "custom css" tab in the Joomla UI for the code? I'm new at doing this so am not so familiar with editing .css files. That said, if I know where exactly to make the change I could.

So if you could help me with the code and what file to change, I'd be very grateful!

Bryan