This is my code. The current problem is temporarily solved with the assistance of the theme company, but I don’t understand what caused it. However, after I installed the demo, the entire website page is messy, layout, style, and more. The lines and icons are not where they should be. The theme support staff told me that it was because of SSL settings, and they reinstalled the SSL plugin recommended by WP. I was worried because the multi-site version was not compatible with their theme.