Kavi mobile style

@jasonlally Mind reviewing my pull request?

Things fixed
- Fixes gutters on mobile
- Styles full-bleed image text (margin, amt of drop shadow, learn more button)
- Fixes submit button on mobile (hides it under hamburger for now)
- Adds style to number callouts on main page (centering, font weights, etc)
- Fixes sponsor padding in footer
- Centers callouts on get involved page (centering
- Small tweaks to community page removed 'lead' from paragraph text, adds padding to map