#004A80

CSS

:root {
  --mermaid-blues: #004a80;
  --mermaid-blues-rgb: 0 74 128;
  --mermaid-blues-oklch: oklch(0.401 0.11 248.9);
}

.element {
  color: var(--mermaid-blues);
  background-color: hsl(205 100% 25%);
  border-color: oklch(0.401 0.11 248.9);
}

Tailwind CSS v4

@theme {
  --color-mermaid-blues: #004a80;
  --color-mermaid-blues-50: #dff8ff;
  --color-mermaid-blues-100: #cdebff;
  --color-mermaid-blues-200: #b2d8ff;
  --color-mermaid-blues-300: #8dbcee;
  --color-mermaid-blues-400: #69a4dd;
  --color-mermaid-blues-500: #458bcc;
  --color-mermaid-blues-600: #3b75ac;
  --color-mermaid-blues-700: #2f5e8a;
  --color-mermaid-blues-800: #1f4566;
  --color-mermaid-blues-900: #143048;
  --color-mermaid-blues-950: #061c2f;
}

SCSS

$mermaid-blues: #004a80;
$mermaid-blues-rgb: 0, 74, 128;
$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);
}