You could do this by giving each poetry page a specific CSS class in the top-of-the-page YAML:
```YAML
---
cssclass: poetry
---
```
And then create a CSS snippet in your vault that styles pages that have the YAML header:
```css
/* verses text */
.markdown-preview-view.poetry {
font-size: 1em;
font-style: italic;
text-align: center;
}
/* heading h1 */
.markdown-preview-view.poetry h1 {
font-size: 2em;
text-transform: uppercase;
}
```
See the following for reference.
Angel