#3A7C99

CSS

:root {
  --cry-me-a-river: #3a7c99;
  --cry-me-a-river-rgb: 58 124 153;
  --cry-me-a-river-oklch: oklch(0.556 0.081 229.4);
}

.element {
  color: var(--cry-me-a-river);
  background-color: hsl(198 45% 41%);
  border-color: oklch(0.556 0.081 229.4);
}

Tailwind CSS v4

@theme {
  --color-cry-me-a-river: #3a7c99;
  --color-cry-me-a-river-50: #dffaff;
  --color-cry-me-a-river-100: #ceedfe;
  --color-cry-me-a-river-200: #b2dbf1;
  --color-cry-me-a-river-300: #8dbfda;
  --color-cry-me-a-river-400: #6aa8c5;
  --color-cry-me-a-river-500: #4690b1;
  --color-cry-me-a-river-600: #3c7a95;
  --color-cry-me-a-river-700: #306278;
  --color-cry-me-a-river-800: #204858;
  --color-cry-me-a-river-900: #15323e;
  --color-cry-me-a-river-950: #061e27;
}

SCSS

$cry-me-a-river: #3a7c99;
$cry-me-a-river-rgb: 58, 124, 153;
$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);
}