# Design your checkout
Customize offer pages, blocks, themes, mobile behavior, and brand details without changing your site embed code.
Source: /docs/offers/design
Last modified: 2026-06-18
Offer design lives in Plandalf. Your public page usually only needs the offer slug and SDK options.

## What you can design

- page structure and block order
- heading, text, image, and HTML blocks
- product summaries and payment blocks
- option selectors, add-ons, and upsells
- brand colors, type, spacing, borders, and radius
- mobile layout and page progression
- close behavior and confirmation copy

## Embed stays stable

Changing design inside the offer does not require replacing your site button:

```html
<button data-plandalf-present="pro-plan">
  Buy Pro
</button>
```

The next time the SDK opens `pro-plan`, it uses the current published offer state.

## Use real test sessions

Preview layout in the editor, then run a test session to verify the complete customer path:

- required fields
- payment methods
- totals, taxes, and discounts
- add-ons and upsells
- mobile frame behavior
- redirects and automations

## Related docs

- [Configure frame and size](/docs/sdk/configure)
- [Multi-page flows](/docs/offers/multi-page-flows)
- [Going live](/docs/going-live)