#8A9EA1

CSS

:root {
  --inland-waters: #8a9ea1;
  --inland-waters-rgb: 138 158 161;
  --inland-waters-oklch: oklch(0.685 0.023 207.6);
}

.element {
  color: var(--inland-waters);
  background-color: hsl(188 11% 59%);
  border-color: oklch(0.685 0.023 207.6);
}

Tailwind CSS v4

@theme {
  --color-inland-waters: #8a9ea1;
  --color-inland-waters-50: #eef7f9;
  --color-inland-waters-100: #e0eaec;
  --color-inland-waters-200: #cad7da;
  --color-inland-waters-300: #abbbbe;
  --color-inland-waters-400: #8fa3a5;
  --color-inland-waters-500: #758b8e;
  --color-inland-waters-600: #637578;
  --color-inland-waters-700: #4f5e60;
  --color-inland-waters-800: #394546;
  --color-inland-waters-900: #273031;
  --color-inland-waters-950: #151c1d;
}

SCSS

$inland-waters: #8a9ea1;
$inland-waters-rgb: 138, 158, 161;
$inland-waters-light: mix(#fff, $inland-waters, 20%);
$inland-waters-dark: mix(#000, $inland-waters, 20%);

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