Motion sensor activated LED in a light box, rechargeable power pack

[Smartmrhawkins]

Hello forum, I've never built anything before and would love some help / advice.

I have a light box and want to put a motion sensor on the outside so that it triggers a light on the inside. I would like the power pack to be rechargeable by USB (if possible) and discreetly hidden inside the light box.

All suggestions are welcome!