#65A1C9

CSS

:root {
  --sub-zero: #65a1c9;
  --sub-zero-rgb: 101 161 201;
  --sub-zero-oklch: oklch(0.684 0.086 239);
}

.element {
  color: var(--sub-zero);
  background-color: hsl(204 48% 59%);
  border-color: oklch(0.684 0.086 239);
}

Tailwind CSS v4

@theme {
  --color-sub-zero: #65a1c9;
  --color-sub-zero-50: #e0f9ff;
  --color-sub-zero-100: #cfecff;
  --color-sub-zero-200: #b4daf6;
  --color-sub-zero-300: #90bee0;
  --color-sub-zero-400: #6da6cc;
  --color-sub-zero-500: #4b8eb9;
  --color-sub-zero-600: #40789c;
  --color-sub-zero-700: #33607d;
  --color-sub-zero-800: #22475c;
  --color-sub-zero-900: #173141;
  --color-sub-zero-950: #081d29;
}

SCSS

$sub-zero: #65a1c9;
$sub-zero-rgb: 101, 161, 201;
$sub-zero-light: mix(#fff, $sub-zero, 20%);
$sub-zero-dark: mix(#000, $sub-zero, 20%);

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