#8FCDE9

CSS

:root {
  --below-zero: #8fcde9;
  --below-zero-rgb: 143 205 233;
  --below-zero-oklch: oklch(0.816 0.074 227.9);
}

.element {
  color: var(--below-zero);
  background-color: hsl(199 67% 74%);
  border-color: oklch(0.816 0.074 227.9);
}

Tailwind CSS v4

@theme {
  --color-below-zero: #8fcde9;
  --color-below-zero-50: #e1faff;
  --color-below-zero-100: #d0edfc;
  --color-below-zero-200: #b5dbee;
  --color-below-zero-300: #90bfd6;
  --color-below-zero-400: #6ea8c1;
  --color-below-zero-500: #4b90ad;
  --color-below-zero-600: #417a92;
  --color-below-zero-700: #346175;
  --color-below-zero-800: #234856;
  --color-below-zero-900: #17323c;
  --color-below-zero-950: #081e26;
}

SCSS

$below-zero: #8fcde9;
$below-zero-rgb: 143, 205, 233;
$below-zero-light: mix(#fff, $below-zero, 20%);
$below-zero-dark: mix(#000, $below-zero, 20%);

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