Thank you, Anthony.
1) I'm typing on a brand new MBP that I just got this afternoon so there is zero cache issue
2) The background color I changed to is #969696 or rgb(150,150,150). It still shows to you the default blockquote bg color which is the same as XF stock.
That means the changes made in styles properties do not affect anything. I can't find out why.
3) I made the same changes for XF stock and it works right away.
4) I made changes to Flexile parent style and it does not work.
5) The style I use is a child of Flexile.