Thank you so much ! (´ ∀ `) for the hover effect, I just applied some css filters to make it grayscale & I added a hue-rotate filter on the links for the color transition ! Idk how to explain it well sorry, but you can take a look at my code here where it says "filter": http://arataka.neocities.org/css/shrines.css
Also if you need a list of filters, there's one here ! https://developer.mozilla.org/en-US/docs/Web/CSS/filter
thank you so much !!! i love ur ponyo shrine :>