React Multi Select Component Styling

CSS variables

The field is a .form-control-group, so its frame, the cleaner and the toggle read the --cui-control-* and --cui-control-group-* tokens. className and style on CMultiSelect land on that frame, the .multi-select element, so the tokens can be set on a single field. The selected chips add two of their own:

$multi-select-tokens: defaults(
  (
    --cui-multi-select-selection-chips-gap: .25rem,
    --cui-multi-select-selection-chips-padding-y: .25rem,
  ),
  $multi-select-tokens
);

The options menu is the shared combobox surface, which Autocomplete renders too, so it carries its own set.

$combobox-tokens: defaults(
  (
    --cui-combobox-popup-min-width: 100%,
  ),
  $combobox-tokens
);

Everything inside the panel — the options, the group labels, the select-all button and the checkbox indicator — is a List box and takes its --cui-list-box-* variables. .list-box declares them itself, so a value set on .combobox-popup or on :root does not reach it: set them with a rule on .combobox-popup .list-box, which covers the panels of Combobox, Autocomplete and Multi Select alike.

How to use CSS variables

const customVars = {
  '--cui-control-border-color': 'var(--cui-primary-base)',
  '--cui-multi-select-selection-chips-gap': '.5rem',
}

return <CMultiSelect options={options} style={customVars} />