Module:Message box/fmbox.css

.fmbox {
  background-color: #f8f9fa;
  border: 1px solid #a2a9b1;
  box-sizing: border-box;
  clear: both;
  color: #202122;
  margin: 0.2em 0;
  width: 100%;
}

.fmbox-warning {
  background-color: #ffdbdb;  /* Pink */
  border: 1px solid #bb7070;  /* Dark pink */
}

.fmbox-editnotice {
  background-color: transparent;
}

.fmbox .mbox-text {
  border: none;
  /* @noflip */
  padding: 0.25em 0.9em;
  width: 100%;
}

.fmbox .mbox-image {
  border: none;
  /* @noflip */
  padding: 2px 0 2px 0.9em;
  text-align: center;
}

.fmbox .mbox-imageright {
  border: none;
  /* @noflip */
  padding: 2px 0.9em 2px 0;
  text-align: center;
}

.fmbox .mbox-invalid-type {
  text-align: center;
}

@media screen {
  html.skin-theme-clientpref-night .fmbox-warning {
    background-color: #300;  /* Reddish, same hue/saturation as light */
  }
}

@media screen and ( prefers-color-scheme: dark) {
  html.skin-theme-clientpref-os .fmbox-warning {
    background-color: #300;  /* Reddish, same hue/saturation as light */
  }
}