Request for feedback on UI

I am building HitMVP.com which helps app founders plan and manage the development of their app projects. Screenshot is at https://pbs.twimg.com/media/GhPlWImaAAExztB?format=jpg&name=large [Problem] This is essentially a simplified project management system in which the user can write lots of notes and brainstorm their idea in a structured manner. I want to highlight the editable areas by showing an inset shadow (zoom image at 100% to see the borders). The rest of the page has a light gray background, and the editable sections have white backgrounds. Is this intuitive enough to separate it from the rest of the UI? What other ideas do you suggest I can use to make it more intuitive that these areas are editable (Maybe show a tooltip or blinking cursor, etc)? Please advise.