After searching around the forum I have a general sense of what the X theme breakpoints are. In my code, I was able to mimic your breakpoints, but I have noticed that throughout the Cornerstone output the media queries output do not actually follow the guidelines you tell us, so it makes targeting certain layout challenges difficult at times. For example, in Cornerstone, I will set up a row layout to be one column up until the LG breakpoint, and then a different layout after that.
However, when inspecting the layout it is not quite right because in the code you are actually targeting this type of layout by way of:
This is problematic because everywhere you look within Cornerstone and within your forums, the LG breakpoint is min-width: 980px, but this code being output cleary considers LG to be min-width: 979px, which ends up resulting in an inaccurate layout.
So, how are developers supposed to truly mimic the breakpoints used by X in order to be able to seamlessly create our own code that will actually match what the Cornerstone builder actually outputs? Thanks.