А вот и наглядное использование контроля стилей через свойства виджета. Билиотека qt-material.
В этом разделе написано, что через свойство class можно контролировать цвет кнопки, по аналогии с css стилями.
btn_danger.setProperty('class', 'danger')
btn_warning.setProperty('class', 'warning')
btn_success.setProperty('class', 'success')
#libs#qt
https://github.com/aio-libs/aiohttp-mako
#mako template renderer for #aiohttp.web based on aiohttp_jinja2. Library has almost same api and support python 3.5 (PEP492) syntax. It is used in aiohttp_debugtoolbar.
#Mako is a #template library written in Python. It provides a familiar, non-XML syntax which compiles into Python modules for maximum performance. Mako's syntax and #API borrows from the best ideas of many others, including #Django and #Jinja2 templates, #Cheetah, #Myghty, and #Genshi. Conceptually, Mako is an embedded Python (i.e. Python Server Page) language, which refines the familiar ideas of componentized layout and inheritance to produce one of the most straightforward and flexible models available, while also maintaining close ties to Python calling and scoping semantics.
http://www.makotemplates.org/