The `{% raw %}{% ... %}{% endraw %}` bit is the [Tera templating language](https://keats.github.io/tera/docs/) (it's meant to look like Jinja, if you're familiar with that). This syntax is how we do fun templating things -- in this case, we're creating a `block` that other pages can fill later.
Let's go back to `input/index.md` and use this layout.
```md
{%- raw -%}{% extends "../layouts/base.tera" %}
{% block body %}{% endraw -%}
# Hello, world!
This is my new site!{% raw -%}
{% endblock body %}{% endraw -%}
```
Build the site again, host it, and look at the result. There should be a title that says "My New Site!" and the content should be the same. Check out the `output` folder to get an idea of how Roxy builds and structures files.
Tera has many more features to explore, so I'd highly recommend looking at the [documentation](https://keats.github.io/tera/docs/).