Minimal Typography for FastHTML Apps

When using `pico=False` and no CSS framework, a FastHTML page doesn't look great. Can we use minimal typography to make it look decent, without dependencies?
## Setup
```python from fasthtml.common import * from fasthtml.jupyter import * ```
## Styling the Bare Minimum
I style `:root` because it's the highest-level CSS selector. The bare minimum to make a page look decent is `font-family`:
```python css = ':root {font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;} p {line-height: 1.5;}' s = Style(css) s ```
```python d = Div(s, H1("Typography Experiment"), P("Here's a paragraph of text for testing. "*20)) show(d) ```
## Constraining Width
The only thing remaining to make the text look good is to constrain the width. Best to do that in a container div.
```python css = ':root {font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;} p {line-height: 1.5;} #container {width: 800px; margin: 0 auto;}' s = Style(css) d = Div(s, H1("Typography Experiment"), P("Here's a paragraph of text for testing. "*20), id="container") show(d) ```
## FastHTML App
Putting it into a page in a FastHTML app:
```python app, rt = fast_app(pico=False) ```
Here I run Uvicorn from this notebook. Replace this with `serve()` at the bottom if you are using this in a main.py:
```python server = JupyUvi(app) ```
```python @rt def index(): return Div( Style(css), H1("Typography Experiment"), P("Here's a paragraph of some text. "*20), id="container" ) ```
## Stop Server
Run this cell to stop Uvicorn:
```python if 'server' in globals: server.stop() ```