Hēi Sè Black

CSS

:root {
  --hei-se-black: #142030;
  --hei-se-black-rgb: 20 32 48;
  --hei-se-black-oklch: oklch(0.241 0.035 255.9);
}

.element {
  color: var(--hei-se-black);
  background-color: hsl(214 41% 13%);
  border-color: oklch(0.241 0.035 255.9);
}

Tailwind CSS v4

@theme {
  --color-hei-se-black: #142030;
  --color-hei-se-black-50: #eff6ff;
  --color-hei-se-black-100: #e1e9f4;
  --color-hei-se-black-200: #cbd5e4;
  --color-hei-se-black-300: #acb8ca;
  --color-hei-se-black-400: #91a0b4;
  --color-hei-se-black-500: #77889e;
  --color-hei-se-black-600: #657385;
  --color-hei-se-black-700: #515c6b;
  --color-hei-se-black-800: #3a434f;
  --color-hei-se-black-900: #282e37;
  --color-hei-se-black-950: #161b22;
}

SCSS

$hei-se-black: #142030;
$hei-se-black-rgb: 20, 32, 48;
$hei-se-black-light: mix(#fff, $hei-se-black, 20%);
$hei-se-black-dark: mix(#000, $hei-se-black, 20%);

.element {
  color: $hei-se-black;
  box-shadow: 0 0 0 2px rgba($hei-se-black, 0.35);
}