Fixes MER-1750: use custom stylesheet from DND layout if present. (At some point code had regressed to lose this). This is crucial for chemistry which has examples embedding images via background-image styles.
Adds new test of this from chemistry to migration course. Also adds missing background image resource for a previously existing DND test.
Fixes MER-1750: use custom stylesheet from DND layout if present. (At some point code had regressed to lose this). This is crucial for chemistry which has examples embedding images via background-image styles.
Adds new test of this from chemistry to migration course. Also adds missing background image resource for a previously existing DND test.