#7B6951

CSS

:root {
  --heavy-brown: #7b6951;
  --heavy-brown-rgb: 123 105 81;
  --heavy-brown-oklch: oklch(0.532 0.042 74.6);
}

.element {
  color: var(--heavy-brown);
  background-color: hsl(34 21% 40%);
  border-color: oklch(0.532 0.042 74.6);
}

Tailwind CSS v4

@theme {
  --color-heavy-brown: #7b6951;
  --color-heavy-brown-50: #fcf4e8;
  --color-heavy-brown-100: #f0e6d9;
  --color-heavy-brown-200: #dfd2c1;
  --color-heavy-brown-300: #c4b5a0;
  --color-heavy-brown-400: #ae9b83;
  --color-heavy-brown-500: #978367;
  --color-heavy-brown-600: #806f58;
  --color-heavy-brown-700: #665846;
  --color-heavy-brown-800: #4c4032;
  --color-heavy-brown-900: #342c22;
  --color-heavy-brown-950: #201911;
}

SCSS

$heavy-brown: #7b6951;
$heavy-brown-rgb: 123, 105, 81;
$heavy-brown-light: mix(#fff, $heavy-brown, 20%);
$heavy-brown-dark: mix(#000, $heavy-brown, 20%);

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