Black River Falls

CSS

:root {
  --black-river-falls: #343e54;
  --black-river-falls-rgb: 52 62 84;
  --black-river-falls-oklch: oklch(0.364 0.04 265.5);
}

.element {
  color: var(--black-river-falls);
  background-color: hsl(221 24% 27%);
  border-color: oklch(0.364 0.04 265.5);
}

Tailwind CSS v4

@theme {
  --color-black-river-falls: #343e54;
  --color-black-river-falls-50: #f0f5ff;
  --color-black-river-falls-100: #e2e8f6;
  --color-black-river-falls-200: #cdd4e6;
  --color-black-river-falls-300: #aeb7cd;
  --color-black-river-falls-400: #939eb7;
  --color-black-river-falls-500: #7986a2;
  --color-black-river-falls-600: #677289;
  --color-black-river-falls-700: #525b6e;
  --color-black-river-falls-800: #3b4351;
  --color-black-river-falls-900: #292e38;
  --color-black-river-falls-950: #161b23;
}

SCSS

$black-river-falls: #343e54;
$black-river-falls-rgb: 52, 62, 84;
$black-river-falls-light: mix(#fff, $black-river-falls, 20%);
$black-river-falls-dark: mix(#000, $black-river-falls, 20%);

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