tootlab-mastodon/app/javascript/flavours/glitch/styles/accessibility.scss

$emojis-requiring-inversion: 'back' 'copyright' 'curly_loop' 'currency_exchange'
  'end' 'heavy_check_mark' 'heavy_division_sign' 'heavy_dollar_sign'
  'heavy_minus_sign' 'heavy_multiplication_x' 'heavy_plus_sign' 'on'
  'registered' 'soon' 'spider' 'telephone_receiver' 'tm' 'top' 'wavy_dash' !default;

%emoji-color-inversion {
  filter: invert(1);
}

.emojione {
  @each $emoji in $emojis-requiring-inversion {
    &[title=':#{$emoji}:'] {
      @extend %emoji-color-inversion;
    }
  }
}

// Display a checkmark on active UI elements otherwise differing only by color
.status__action-bar-button,
.detailed-status__button .icon-button {
  position: relative;

  &.active::after {
    position: absolute;
    content: '\F00C';
    font-size: 50%;
    font-family: FontAwesome;
    right: -0.55em;
    top: -0.44em;
  }
}

.hicolor-privacy-icons {
  .status__visibility-icon.fa-globe,
  .privacy-dropdown__option .fa-globe {
    color: #1976d2;
  }

  .status__visibility-icon.fa-unlock,
  .privacy-dropdown__option .fa-unlock {
    color: #388e3c;
  }

  .status__visibility-icon.fa-lock,
  .privacy-dropdown__option .fa-lock {
    color: #ffa000;
  }

  .status__visibility-icon.fa-envelope,
  .privacy-dropdown__option .fa-envelope {
    color: #d32f2f;
  }
}