overleaf/services/web/frontend/stylesheets/ds/theme.scss

:root {
  // Default to the light theme
  --ds-color-bg-default: var(--ds-color-white);
  --ds-color-text-primary: var(--ds-color-neutral-900);
  --ds-color-text-secondary: var(--ds-color-neutral-800);
  --ds-color-text-disabled: var(--ds-color-neutral-500);
  --ds-color-text-danger-default: var(--ds-color-red-700);
  --ds-color-text-danger-hover: var(--ds-color-red-800);
  --ds-color-text-warning-default: var(--ds-color-yellow-900);
  --ds-color-text-warning-hover: var(--ds-color-yellow-950);
  --ds-color-text-info-default: var(--ds-color-blue-700);
  --ds-color-text-info-hover: var(--ds-color-blue-800);
  --ds-color-text-success-default: var(--ds-color-green-700);
  --ds-color-text-success-hover: var(--ds-color-green-800);

  .ds-theme-dark {
    --ds-color-bg-default: var(--ds-color-neutral-950);
    --ds-color-text-primary: var(--ds-color-white);
    --ds-color-text-secondary: var(--ds-color-neutral-50);
    --ds-color-text-disabled: var(--ds-color-neutral-500);
    --ds-color-text-danger-default: var(--ds-color-red-700);
    --ds-color-text-danger-hover: var(--ds-color-red-800);
    --ds-color-text-warning-default: var(--ds-color-yellow-900);
    --ds-color-text-warning-hover: var(--ds-color-yellow-950);
    --ds-color-text-info-default: var(--ds-color-blue-700);
    --ds-color-text-info-hover: var(--ds-color-blue-800);
    --ds-color-text-success-default: var(--ds-color-green-700);
    --ds-color-text-success-hover: var(--ds-color-green-800);
  }
}