Here’s the list of fonts WK uses in order:
- Hiragino Kaku Gothic Pro
- Meiryo
- Source Han Sans Japanese
- NotoSansCJK
- TakaoPGothic
- Yu Gothic
- ヒラギノ角ゴ Pro W3
- メイリオ
- Osaka
- MS PGothic
- MS Pゴシック
- sans-serif
It will start from the top of the list and go until it finds a font either on your computer or included on the site.
If you’re running Windows 10 like I am, you’re probably normally defaulting to Yu Gothic. I went out and found Hiragino Kaku, so that’s what it defaults to for me.
Here’s a comparison between Hiragino Kaku and Yu Gothic for reference:
You can see the Hiragino font is quite a lot thicker and slightly larger. Since it’s the first in the list, I suppose you could call Hiragino the “official” way WK is supposed to look.