the author describes how their render-once approach lets them implement CSS in a simpler way since they don't need to retain information for arbitrary dynamic changes in the stylesheets and content
they also probably don't implement most of CSS
they also probably don't implement most of CSS
For the rotation I could process a second layout on the background and switch to it instantly if rotated. Similarly hover effects will be limited. Things affecting visibility of the blocks/layers should work (for menus), small adjustments of layouted text too, but anything that is more complicated won't be. It currently uses a hardcoded hover effect for links.