See section "Reference: Custom master pages and the workflow designer" (2010) and "Style Guide" (2007) of the SDK for further guidance on working with custom branding and Nintex.
Nintex Workflow 2010 SDK
Nintex Workflow 2007 SDK
This this a question on how to create a custom brand for all new Nintex forms?
Essentially you would style a sample form on a custom list, remove all the controls, export the form and import it into Central Admin as a form layout. Each new form created will have these styles applied (existing forms are not affected). For a step-by-step guide you can follow this guide: Branding Nintex Forms
Branding does not seem to be as import now in Nintex Forms 2013 since the default template (and their CSS) is actually ok unlike the awful default colours in the 2010 Nintex Forms.
Hi Jan, Rob,
Thanks for your valuable input! This was specifically around custom branding of SharePoint sites and how they can affect the Nintex Workflow designer page.
The latest release includes an important change too that allows you to set the OOTB Master Page from Central Admin for pages where the Nintex Workflow designer is opened! (Release Nintex Workflow 2010 18.104.22.168)
Central Admin > NintexWorkflow Management >> Global Settings >> Master Page for Designer
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