metamask-extension/ui/css/design-system/deprecated-colors.scss

/**
  These colors are either deprecated or will move into colors.scss
  when approved for the design system
**/

// These are declared as variables and hoisted because they are
// used as rgba's and native rgba doesn't accept var()
$alto: #dedede;
$black: #000;
$white: #fff;
$monzo: #d0021b;