# Aspect ratio & transitions

| `aspectRatio`    | Design size |
| ---------------- | ----------- |
| `16:9` (default) | 1280 × 720  |
| `4:3`            | 1024 × 768  |

Slides are designed at a fixed size and scaled to fit the screen, an embed or a PDF page.

| `transition`      | Effect                     |
| ----------------- | -------------------------- |
| `slide` (default) | directional slide and fade |
| `fade`            | cross-fade                 |
| `none`            | instant                    |

Set it for the deck (`deck.transition`) or per slide (`--- transition=fade`). The pitch deck is 4:3
with fade transitions:

<StoryEmbed slug="pitch" slide={2} />