Style marine sanctuaries differently about openstreetmap-americana

[zekefarwell]

Originally posted as a comment on #49, but more relevant here:

Many protected area boundaries cross water and land, so the styling absolutely has to contrast well with both. Using a different style for marine sanctuaries is not a solution to that problem. However, since marine sanctuaries are entirely over water a different style could look much better especially at low zoom levels.

On the coast of Massachusetts for example, there are two large protected areas. The boundary of Cape Cod National Seashore crosses land and water, but stays close to the coast. At low zoom this is barely visible and the boundary line just looks like it's on the shore. On the other hand, the boundary of Stellwagen Bank National Marine Sanctuary is entirely in the ocean. The coast of California also has many of these marine protected areas sticking far out into the ocean.

Using a blue outline where the boundary is entirely or mostly over water would be a nice cartographic effect and less distracting than a green outline in the middle of the ocean. We could also decide to simply exclude marine sanctuaries on the basis that this map style focuses on land based features.

[1ec5]

There is currently a stand-off between water color and protected area boundary line color that results in water coloring that is probably a little too dark, but provides a nice contrast with the boundary lines.

The lighter water color in #610 helps the protected area boundaries blend in a little more.