Hi, When I export / publish website the design and layout look completely different. This is an example
You have this twice, its effecting all children in the row, so the columns are being overridden to 100% width
You seem to have the bootstrap css in your design twice, first as the bootstrap.min.css and then you have what looks like a custom version of the bootstrap css in your styles.min.css
You might want to look here Themes | Bootstrap Studio on how to use a custom theme in your design