Text in Goat diagrams is too big

[jhenstridge]

I tried using Hugo's Goat diagram feature, and found that the text is too big when using the Ananke theme.

For example, the following diagram:

```goat
.-------------.
| hello world |
'-------------'
```

... is rendered as:

The diagram is converted to embedded SVG, with the text rendered in a fixed width font intended to fit the grid. The problem seems to be from the f4 class applied to the parent div containing the page content, setting the font-size:1.25rem. If I disable that style, the diagram renders a bit better:

I'm not sure what the best way to fix this would be.