#285A0A

CSS

:root {
  --lincoln-green: #285a0a;
  --lincoln-green-rgb: 40 90 10;
  --lincoln-green-oklch: oklch(0.417 0.119 137.1);
}

.element {
  color: var(--lincoln-green);
  background-color: hsl(98 80% 20%);
  border-color: oklch(0.417 0.119 137.1);
}

Tailwind CSS v4

@theme {
  --color-lincoln-green: #285a0a;
  --color-lincoln-green-50: #e4fedd;
  --color-lincoln-green-100: #d4f2cc;
  --color-lincoln-green-200: #bbe1b0;
  --color-lincoln-green-300: #98c78b;
  --color-lincoln-green-400: #7caf67;
  --color-lincoln-green-500: #5e9844;
  --color-lincoln-green-600: #50813b;
  --color-lincoln-green-700: #40672f;
  --color-lincoln-green-800: #2f4b1f;
  --color-lincoln-green-900: #203414;
  --color-lincoln-green-950: #102006;
}

SCSS

$lincoln-green: #285a0a;
$lincoln-green-rgb: 40, 90, 10;
$lincoln-green-light: mix(#fff, $lincoln-green, 20%);
$lincoln-green-dark: mix(#000, $lincoln-green, 20%);

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