After updated the latest Specular theme, I found that my single post content layout was changed and it also happened to show breadcrumbs under my menu bar(which never happen before).
However, I tried to remove the header page and breadcrumbs using css code in other users’ forum and it worked. Anyway I still have a problem with my post content layout.
Previously, my post content layout is full width (selected “Modern” style). But currently it seem to be squeezed to center, not in a full width style anymore.
