I am not entirely sure about it, but IIRC the shown font is dependent on your device, because I remember seeing different styles of characters when using the site from my linux laptop instead of my windows one.
Anyway, you can figure it out by yourself, if you use Edge browser or Chrome (the process for other browsers should be similar):
1) Open the menu by clicking ... in the top right corner
2) Click "more tools" (or similar)
3) Click on Developer Tools and a developer window will open.
4) On the Developer Tools window, click on the inspect button (the one with a rectangle shape with a mouse cursor on it)
5) Go back to the actual page displaying the character and hover over it.
6) A modal will pop up showing the used font for the character (alongside other info).
In my case, the font is "Source Han Sans".
I uploaded two screenshots so you can follow through the steps 1 to 6 more easily:
https://ibb.co/bKRtcgy
https://ibb.co/0VgCn0d
Cheers!
Sorry, I reread your question and realized you were asking specifically about the change displayed when you hover the mouse. To find it, you need to do the steps 1 to 6 and then:
7) Click on the kanji in the website to select the html element and check the "styles" tab.
8) take a look at the css selector "._kanji_light .character:hover" to find out the font for when you hover. In my case, it is "HiraMinProN-W3".
Find the screenshot for theses steps here:
Hope it helps!
That's a helpful answer, thanks! And sorry for seeing your answer late too.
No worries, we are all busy, I am glad it was helpful. Thanks for taking the time to appreciate it :)
Which font is used on the kanji when you hover over your mouse on it?
I would like to use that font while studying.