Can't set margin on calendar container

Due to the way this is implemented, you can't set margins on the container itself.
For example, the library uses DEVICE_WIDTH everywhere. Meaning, we have to override the styles and subtract the margin everywhere that DEVICE_WIDTH is used.

Start by tracing every use of DEVICE_WIDTH in the calendar implementation and determine how the container dimensions are calculated. The work is complete when a consumer can apply margins to the calendar container without overriding styles or manually subtracting those margins from each DEVICE_WIDTH use.

Written by the indexing model from the issue text.