* due to xblocks being placed in various UI, mediaqueries can't be used reliably
* xblocks cannot get information on their parent element's dimensions
* t-shirt-based sizing, based on responsively made media queries, was recommended given these constraints
* sizes include: xs, s, m, l, xl and correspond to sass variables that have been previously used for native media queries
* this is less than idea but needed and causes: gaps in transitions; a manual class to be added to the .xblock classed HTML element; bloat/redundancy in compiled CSS