Baseof.html can't be found

Hugo Version: v0.32.2

When I try to use baseof.html only with only a theme, it is not working, I can’t see my single article.

I created a /themes/[theme]/layouts/_default/baseof.html. After that, I tried to verify my code is working on a single article. So I go directly to the page. After that, I found out a 404 page.

Did you implement the 10th case of the template? Is it working? Should I use segment differently?