#AA3E00

CSS

:root {
  --rust: #aa3e00;
  --rust-rgb: 170 62 0;
  --rust-oklch: oklch(0.509 0.154 42);
}

.element {
  color: var(--rust);
  background-color: hsl(22 100% 33%);
  border-color: oklch(0.509 0.154 42);
}

Tailwind CSS v4

@theme {
  --color-rust: #aa3e00;
  --color-rust-50: #ffe8d2;
  --color-rust-100: #ffd8bf;
  --color-rust-200: #ffbf9f;
  --color-rust-300: #f99d75;
  --color-rust-400: #e87c51;
  --color-rust-500: #d65b22;
  --color-rust-600: #b54e20;
  --color-rust-700: #913e19;
  --color-rust-800: #6d2c13;
  --color-rust-900: #4d1d0c;
  --color-rust-950: #320d01;
}

SCSS

$rust: #aa3e00;
$rust-rgb: 170, 62, 0;
$rust-light: mix(#fff, $rust, 20%);
$rust-dark: mix(#000, $rust, 20%);

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