I have an old VF page that now needs to be displayed in Lightning. So I checked the checkbox
Available for Salesforce mobile apps and Lightning Pagesfor the page.
But the styles seem to override. The page does not use
header. What could I be missing here!
Opting for Lightning Design System here, may need a lot of rework on the whole page.
At Dreamforce ’15, there were several mentions on Roadmap slide decks about auto-styling of classic Visualforce elements (pageBlock, inputField, etc.). There was no date given of when this functionality would be available, but depending on how immediate your need is, waiting it out is also an option.