#617C5B

CSS

:root {
  --emerald-city: #617c5b;
  --emerald-city-rgb: 97 124 91;
  --emerald-city-oklch: oklch(0.556 0.059 140);
}

.element {
  color: var(--emerald-city);
  background-color: hsl(109 15% 42%);
  border-color: oklch(0.556 0.059 140);
}

Tailwind CSS v4

@theme {
  --color-emerald-city: #617c5b;
  --color-emerald-city-50: #ecfaea;
  --color-emerald-city-100: #ddeddb;
  --color-emerald-city-200: #c7dbc4;
  --color-emerald-city-300: #a7c0a4;
  --color-emerald-city-400: #8ca786;
  --color-emerald-city-500: #72906b;
  --color-emerald-city-600: #607a5b;
  --color-emerald-city-700: #4d6248;
  --color-emerald-city-800: #384733;
  --color-emerald-city-900: #273123;
  --color-emerald-city-950: #151d12;
}

SCSS

$emerald-city: #617c5b;
$emerald-city-rgb: 97, 124, 91;
$emerald-city-light: mix(#fff, $emerald-city, 20%);
$emerald-city-dark: mix(#000, $emerald-city, 20%);

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