Calling a default widget in to a custom widget

Hello All,

We are working on a Customization in our Community and we are in the beginner stage 

  • Is it possible to call a widget in the same widget

User case: We have a Custom widget(A) and planning to call one more widget in the same widget(A).Is it possible if you so can anyone provide a code snippet

  • We observed there are 2 ways to configure CSS in the Community. One is adding the CSS content directly to the widget and one more adding all CSS in the theme page. Can someone suggest which is the best Approach