#357EA1

CSS

:root {
  --cry-me-a-river: #357ea1;
  --cry-me-a-river-rgb: 53 126 161;
  --cry-me-a-river-oklch: oklch(0.562 0.09 232.4);
}

.element {
  color: var(--cry-me-a-river);
  background-color: hsl(199 50% 42%);
  border-color: oklch(0.562 0.09 232.4);
}

Tailwind CSS v4

@theme {
  --color-cry-me-a-river: #357ea1;
  --color-cry-me-a-river-50: #ddfaff;
  --color-cry-me-a-river-100: #cceeff;
  --color-cry-me-a-river-200: #afdbf5;
  --color-cry-me-a-river-300: #8ac0df;
  --color-cry-me-a-river-400: #65a8cb;
  --color-cry-me-a-river-500: #3e90b8;
  --color-cry-me-a-river-600: #367a9b;
  --color-cry-me-a-river-700: #2b627c;
  --color-cry-me-a-river-800: #1c485c;
  --color-cry-me-a-river-900: #123240;
  --color-cry-me-a-river-950: #041e29;
}

SCSS

$cry-me-a-river: #357ea1;
$cry-me-a-river-rgb: 53, 126, 161;
$cry-me-a-river-light: mix(#fff, $cry-me-a-river, 20%);
$cry-me-a-river-dark: mix(#000, $cry-me-a-river, 20%);

.element {
  color: $cry-me-a-river;
  box-shadow: 0 0 0 2px rgba($cry-me-a-river, 0.35);
}