How does my completely blank Wordpress theme works?

问题

I made a test. i have a Wordpress site using Elementor page builder (pages, archives, header, footer... everything made with Elementor page builder).

Now i made a theme which contains only two files:

index.php
style.css

The index.php file is completely blank. nothing inside it. The style.css file contains the basic theme config comment thing.

Everything works great on the site. and my question is why?

For example how does the head part adds the used plugins if the theme doesn't contain wp_head() any where?

Also (Second Question) - what am i missing? where would this completely blank theme will fail?

来源：https://stackoverflow.com/questions/56322397/how-does-my-completely-blank-wordpress-theme-works