#004473

CSS

:root {
  --mermaid-blues: #004473;
  --mermaid-blues-rgb: 0 68 115;
  --mermaid-blues-oklch: oklch(0.377 0.1 247.4);
}

.element {
  color: var(--mermaid-blues);
  background-color: hsl(205 100% 23%);
  border-color: oklch(0.377 0.1 247.4);
}

Tailwind CSS v4

@theme {
  --color-mermaid-blues: #004473;
  --color-mermaid-blues-50: #e0f8ff;
  --color-mermaid-blues-100: #cfebff;
  --color-mermaid-blues-200: #b4d8fe;
  --color-mermaid-blues-300: #90bce9;
  --color-mermaid-blues-400: #6da4d7;
  --color-mermaid-blues-500: #4b8bc5;
  --color-mermaid-blues-600: #4076a6;
  --color-mermaid-blues-700: #335e85;
  --color-mermaid-blues-800: #224663;
  --color-mermaid-blues-900: #163045;
  --color-mermaid-blues-950: #071c2d;
}

SCSS

$mermaid-blues: #004473;
$mermaid-blues-rgb: 0, 68, 115;
$mermaid-blues-light: mix(#fff, $mermaid-blues, 20%);
$mermaid-blues-dark: mix(#000, $mermaid-blues, 20%);

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