#004975

CSS

:root {
  --mermaid-blues: #004975;
  --mermaid-blues-rgb: 0 73 117;
  --mermaid-blues-oklch: oklch(0.391 0.097 244.3);
}

.element {
  color: var(--mermaid-blues);
  background-color: hsl(203 100% 23%);
  border-color: oklch(0.391 0.097 244.3);
}

Tailwind CSS v4

@theme {
  --color-mermaid-blues: #004975;
  --color-mermaid-blues-50: #dff9ff;
  --color-mermaid-blues-100: #ceecff;
  --color-mermaid-blues-200: #b3d9fc;
  --color-mermaid-blues-300: #8fbde7;
  --color-mermaid-blues-400: #6ba5d4;
  --color-mermaid-blues-500: #488cc2;
  --color-mermaid-blues-600: #3e77a4;
  --color-mermaid-blues-700: #315f83;
  --color-mermaid-blues-800: #214661;
  --color-mermaid-blues-900: #163144;
  --color-mermaid-blues-950: #071d2c;
}

SCSS

$mermaid-blues: #004975;
$mermaid-blues-rgb: 0, 73, 117;
$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);
}