When dividing the page into 3 columns, the main part became narrow and the design collapsed.
In that case, if you set the overall page width wider than the current one, you can prevent the collapse of the design.
For details, refer to the following page of the manual.
"User Manual> Blog> Customize> Overall> Layout> Page Width"
For details, refer to the following page of the manual.
"User Manual> Blog> Customize> Overall> Layout> Page Width"