I’m not one of those ”oh lets make anime adaptations 1 to 1 stylistically insanely over the top” guys but…
those absolutely are weird hair colors in j-ent terms if you actually pay attention to it.
just look at any of the popular 2010s idols (including akb) and they ALL have black hair, yes the center/ace too. no traditional jpop idol from those times will have brightly colored hair.
and majority of young actresses almost never dye their hair unless it's for a role. if akane's hair was blue she'd give off a rebellious vibe which doesn't align with her character.
if you want their hair colors to be accurate just look at cosplay man
just look at any of the popular 2010s idols (including akb) and they ALL have black hair, yes the center/ace too. no traditional jpop idol from those times will have brightly colored hair.
and majority of young actresses almost never dye their hair unless it's for a role. if akane's hair was blue she'd give off a rebellious vibe which doesn't align with her character.
if you want their hair colors to be accurate just look at cosplay man