You're building a single-page skincare routine tracker that helps users catalog their current products and remember when to use them.

The app should let users **add skincare products** with the following details:
- Product name and brand
- Skin concern it targets (e.g., hydration, acne, SPF, anti-aging)
- Routine slot: Morning, Evening, or Both
- Whether it's currently active or paused (e.g., ran out, testing a replacement)

Users should be able to **view their full product shelf** grouped by Morning and Evening routines, and **toggle a product's active status** without deleting it. They should also be able to delete products they no longer own.

All data must persist in `localStorage` so the shelf survives a page refresh. The interface should feel clean and personal — think a tidy bathroom shelf, not a spreadsheet. Use soft colors, clear typography, and intuitive controls. No backend, no login required.