How wide is your browser? If you resize your browser and shrink it, then the Responsive code kicks in as if you’re viewing from a smaller device like a small Laptop, Tablet, Mobile Phone, etc.
Try opening your browser all the wide and see what happens. Also let me know what size your laptop is.
I have both a larger External Monitor and I’m also viewing from a 13 inch Macbook/Laptop and it’s still showing up perfectly on both.
When I have the browser resized at 1023px and higher on my laptop, the sidebar shows up on the side. If I shrink the browser then of course the sidebar will move to the bottom as it’s designed to since both the content and sidebar can’t fit next to each other in a space that is too small. On smaller browsers, tablets, and mobile phones, the sidebar is supposed to show up at the bottom.
I’ve checked on multiple browsers and it’s showing up fine.