#590000

CSS

:root {
  --spikey-red: #590000;
  --spikey-red-rgb: 89 0 0;
  --spikey-red-oklch: oklch(0.291 0.12 29.2);
}

.element {
  color: var(--spikey-red);
  background-color: hsl(0 100% 17%);
  border-color: oklch(0.291 0.12 29.2);
}

Tailwind CSS v4

@theme {
  --color-spikey-red: #590000;
  --color-spikey-red-50: #ffe9e0;
  --color-spikey-red-100: #ffdad0;
  --color-spikey-red-200: #ffc2b5;
  --color-spikey-red-300: #eea192;
  --color-spikey-red-400: #dc8275;
  --color-spikey-red-500: #c96456;
  --color-spikey-red-600: #aa5549;
  --color-spikey-red-700: #88443a;
  --color-spikey-red-800: #66302b;
  --color-spikey-red-900: #47211d;
  --color-spikey-red-950: #2e100d;
}

SCSS

$spikey-red: #590000;
$spikey-red-rgb: 89, 0, 0;
$spikey-red-light: mix(#fff, $spikey-red, 20%);
$spikey-red-dark: mix(#000, $spikey-red, 20%);

.element {
  color: $spikey-red;
  box-shadow: 0 0 0 2px rgba($spikey-red, 0.35);
}