With the introduction of dark mode in macOS, Safari Technology Preview 68 has released a new feature called prefers-color-scheme which lets us detect whether the user has dark mode enabled with a media query.
As a site based around Apple products, I think it would be pretty cool to support dark mode CSS media queries. Safari is the first major browser to support this and I think other browsers are likely to follow.
I would also suggest adding a toggle in Settings as many people use Chrome who doesn't currently support this.
Below is the media query:
@media (prefers-color-scheme: dark) {
}