UX to Manage multiple sections and sub sections hierarchy

I have to manage Sections and sub-sections under each sections along with their individual Item lists.

Hierarchy is like:

Section 1:

List of items for section 1

          Sub sections 1

          *List of items for sub section 1*

          Sub section 2

          *List of items for sub section 2* 

and many more..

Section 2:

List of items for section 2

           Sub sections 1

           *List of items for sub section 1*

           Sub section 2

          *List of items for sub section 2* 

and many more..

I have represented it in following design but Its looks too complicated. Can anyone suggest me a simplest UX for this.