bolt.new/packages/bolt/app/styles/variables.scss

:root,
:root[data-theme='light'] {
  /* Color Tokens */
  --bolt-background-primary: theme('colors.gray.50');
}

:root,
:root[data-theme='dark'] {
  /* Color Tokens */
  --bolt-background-primary: theme('colors.gray.50');
}

/*
 * Element Tokens
 *
 * Hierarchy: Element Token -> (Element Token | Color Tokens) -> Primitives
 */
:root {
  --header-height: 65px;

  /* App */
  --bolt-elements-app-backgroundColor: var(--bolt-background-primary);
}