What's Changed
* css fixup to nav in index.html by pawelmagnu in https://github.com/open-atmos/PySDM/pull/1419
* improve test coverage for impl.Mesh and products.SufracePrecipitation; introduce Mesh.domain_bottom_surface_area; switch from volume to mass for rainfall counting; improve docstrings (default length of omitted dims, liquid/ice phase). closes 708 by slayoo in https://github.com/open-atmos/PySDM/pull/1399
**Full Changelog**: https://github.com/open-atmos/PySDM/compare/v2.81...v2.82