Note…
In our Theme Options, in Typography, the Content Font Size is set to 1.125rem so it looks like that’s where this is coming from.
… but why would it be applied different in Cornerstone preview and on the front-end?
On the front-end, this rule is applied as “.entry-content {font-size:1.125rem;}”.
While writing this message I just saw that off-canvas content area is outside of the “entry-content” div, so if you design a global block for a modal or off-canvas content area, you will not have the actual final preview in Cornerstone.
Is this something you can consider looking into?
Thank you!