* feat(components): [message-box] add autofocus attribute
* fix: autofocus to be true by default
* docs: message-box autofocus default value
* chore: remove useless comment
* fix: focusStartRef value el
* feat(theme-chalk): dark palette & common color mixins
* chore: move layouts var
* feat: add dark transparent colors for designer
* refactor: remove example-showcase dark bg