A CSS color value per view tab state. Any omitted state keeps its theme default, so a partial
object overrides only the states it names.
An empty string means inherit — that state is unset and falls back to its theme default. This is the only
way to remove a color from a view that already has one: updateOptions merges, so omitting a state leaves
its current color in place, and an empty viewTab object is treated as no change at all.
A CSS color value per view tab state. Any omitted state keeps its theme default, so a partial object overrides only the states it names.
An empty string means inherit — that state is unset and falls back to its theme default. This is the only way to remove a color from a view that already has one:
updateOptionsmerges, so omitting a state leaves its current color in place, and an emptyviewTabobject is treated as no change at all.