Hard to see some SVGs in dark mode

[john-sp]

In dark mode, some SVGs do not show up due to dark background.

[mooskagh]

Easiest would be to have something like this in .css:

@media (prefers-color-scheme: dark) {
  img.invert-if-dark {
    filter: invert(1);
  }
}

and then have way on Hugo side to specify that certain image should have invert-if-dark class.

Or even all .svgs by default:

@media (prefers-color-scheme: dark) {
  img[src$=".svg"] {
    filter: invert(1);
  }
}

but we need to have a way to disable that per image.