Visual glitch in non-rounded dark dialog about nes.css HOT 1 OPEN

I think the aim was to make it similar to Container.is-dark.

scss\elements\containers.scss

&::after {
  position: absolute;
  top: -$border-size * 1.8;
  right: -$border-size * 1.8;
  bottom: -$border-size * 1.8;
  left: -$border-size * 1.8;
  z-index: -1;
  content: "";
  background-color: $base-color;
}

But, since it is difficult to realize on the dialog, I think that absolute is not necessary.
I sent a pull request for this matter.
#474

from nes.css.