I think Suzanne Collins said she visualized Katniss as having mixed-race ancestry. She implied that there could have been a lot of intermarriage between now and Katniss's era.
Katniss herself never refers to anybody as "white" or "black" ; to her the crucial thing is where in Panem they are from.

No, They never described Katniss as being black and I am a person of color who read the books and saw the movies. As you said, olive skin can pertain to Italians, Greeks and many others who are not on the fair side. Really it just means they could have cast anyone as Katniss, they had open range here, however Katniss' sister and mother were described that way and they basically said she looked like her dad.
Now Rue, to me, should have been played by a darker skinned actress. She was described as having dark skin similar to her partner Thresh, I don't think she was as deep in time as him(haven't read the books in a long while) but it is what it is. The roles have been cast and the movie(s) has(ve) been made. The End.

I didn't think so either

Olive skin does not mean dark skin.