:global

nano.put('.foo', {
  color: 'red',
  ':global': {
    '.global_class': {
      border: '1px solid red',
    },
  },
});

.foo { color: red; }
.global_class { border: 1px solid red; }

nano.global({
  '.global_class': {
    border: '1px solid red',
  },
});

import { addon as addonGlobal } from 'nano-css/addon/global';
addonGlobal(nano);