#397DA3

CSS

:root {
  --cry-me-a-river: #397da3;
  --cry-me-a-river-rgb: 57 125 163;
  --cry-me-a-river-oklch: oklch(0.562 0.09 236);
}

.element {
  color: var(--cry-me-a-river);
  background-color: hsl(202 48% 43%);
  border-color: oklch(0.562 0.09 236);
}

Tailwind CSS v4

@theme {
  --color-cry-me-a-river: #397da3;
  --color-cry-me-a-river-50: #defaff;
  --color-cry-me-a-river-100: #cdedff;
  --color-cry-me-a-river-200: #b1dbf7;
  --color-cry-me-a-river-300: #8cbfe1;
  --color-cry-me-a-river-400: #68a7cd;
  --color-cry-me-a-river-500: #428fba;
  --color-cry-me-a-river-600: #3a799d;
  --color-cry-me-a-river-700: #2e617e;
  --color-cry-me-a-river-800: #1e475d;
  --color-cry-me-a-river-900: #143141;
  --color-cry-me-a-river-950: #051d2a;
}

SCSS

$cry-me-a-river: #397da3;
$cry-me-a-river-rgb: 57, 125, 163;
$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);
}