#75696A

CSS

:root {
  --acoustic-brown: #75696a;
  --acoustic-brown-rgb: 117 105 106;
  --acoustic-brown-oklch: oklch(0.532 0.015 11.9);
}

.element {
  color: var(--acoustic-brown);
  background-color: hsl(355 5% 44%);
  border-color: oklch(0.532 0.015 11.9);
}

Tailwind CSS v4

@theme {
  --color-acoustic-brown: #75696a;
  --color-acoustic-brown-50: #f9f3f4;
  --color-acoustic-brown-100: #ede6e6;
  --color-acoustic-brown-200: #dbd2d2;
  --color-acoustic-brown-300: #bfb4b5;
  --color-acoustic-brown-400: #a79b9c;
  --color-acoustic-brown-500: #908283;
  --color-acoustic-brown-600: #7a6e6f;
  --color-acoustic-brown-700: #615859;
  --color-acoustic-brown-800: #474041;
  --color-acoustic-brown-900: #312c2d;
  --color-acoustic-brown-950: #1d191a;
}

SCSS

$acoustic-brown: #75696a;
$acoustic-brown-rgb: 117, 105, 106;
$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);
}