#7D726F

CSS

:root {
  --acoustic-brown: #7d726f;
  --acoustic-brown-rgb: 125 114 111;
  --acoustic-brown-oklch: oklch(0.561 0.015 35.7);
}

.element {
  color: var(--acoustic-brown);
  background-color: hsl(13 6% 46%);
  border-color: oklch(0.561 0.015 35.7);
}

Tailwind CSS v4

@theme {
  --color-acoustic-brown: #7d726f;
  --color-acoustic-brown-50: #f9f4f2;
  --color-acoustic-brown-100: #ece6e4;
  --color-acoustic-brown-200: #dad2d0;
  --color-acoustic-brown-300: #beb5b2;
  --color-acoustic-brown-400: #a79c99;
  --color-acoustic-brown-500: #8f8380;
  --color-acoustic-brown-600: #796f6c;
  --color-acoustic-brown-700: #615956;
  --color-acoustic-brown-800: #47413f;
  --color-acoustic-brown-900: #312d2b;
  --color-acoustic-brown-950: #1d1a19;
}

SCSS

$acoustic-brown: #7d726f;
$acoustic-brown-rgb: 125, 114, 111;
$acoustic-brown-light: mix(#fff, $acoustic-brown, 20%);
$acoustic-brown-dark: mix(#000, $acoustic-brown, 20%);

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