Glad for the theme and the support!
Trying to figure out how to do these things:
-Add borders around posts and widgets (thickness and color adjustable), and so I can change the background color without changing the post background (white)
-Shift post and widgets slightly to the left, without changing their widths
-Remove “no comments yet”
-Remove “Posted on” but keep the date
I hope you are well today and thank you for your questions.
-Add borders around posts and widgets (thickness and color adjustable),
You can try achieving this by adding the following CSS code in the Custom CSS option of your theme on the below path.
Admin Area -> Appearance -> Customize -> Activello Options -> Other -> Custom CSS
border: 1px solid #eee;
Please change the border size 1px and color value in the above code to whatever you want to use by referring the following pages.
and so I can change the background color without changing the post background (white)
I am not sure what you meant by it so please describe it a bit more in detail.
To help us keep support thread separates could you please create new threads for each of your other questions here https://colorlibsupport.com/c/activello/ instead of asking them in your single thread as it makes the thread messy and hard to read.
If you want to you can also add reference of this thread in your newly created thread.
We would be more than happy to help you on your new thread.