A character or person depicted has light brown hair.
As a good rule of thumb, consider:
- Kirisame Marisa and Alice Margatroid have blonde hair (post #1187817)
- Hakurei Reimu and Ibuki Suika have brown hair (post #1074949)
- Toyosatomimi no Miko has light brown hair (post #1355545)
source: danbooru wiki