Outlook
Outlook on Windows renders email with Microsoft Word, not a browser. That single fact is why most signature builders fall apart in it.
Outlook on Windows renders HTML through the Word engine. Flexbox and grid are ignored outright, so every SigFinch layout is built from tables.
A rounded photo has to be round in the file. We bake the crop into the PNG rather than asking CSS to do it.
Word drops margins on table cells, so all our spacing is cell padding. It is the only thing that survives.
A linked image picks up the link underline. Every image we emit carries the declarations that suppress it.
No account, no password. They open their link, check their details, press Copy signature, and follow the Outlook steps on the same page. When the brand changes, the link still works — it never expires.
And the campaign banner inside it can change after they have pasted it, because the signature points at a permanent URL rather than embedding the artwork.