Modify the CSS in Superset to make it better for OpenLMIS users

Superset's dashboards rely on CSS for their presentation layer. This epic focuses on modifying Superset's dashboard CSS so that dashboards display better when used by OpenLMIS.

Tasks include:

• Make charts responsive in the dashboard to different screen sizes

• Remove headers in dashboards to improve iframe display

• Update the look and feel to be better aligned with the OpenLMIS style guide