Alternatively, to make PDF invoices/receipts with markdown files [markdown themes](https://support.typora.io/About-Themes/) can be used. `theme/cotech.css` can be used as a CSS stylesheet and `invoice_template_themed.md` as template. Images path has to point to `img/` directory at the root of the repository. Invoices in `invoices/sent/2020` were created that way.