Bakers who keep a sourdough starter need to feed it regularly with flour and water, but the math gets confusing fast — especially when scaling up for a big bake day.

Build a single-page widget where a user enters:
- **Current starter weight** (in grams)
- **Desired hydration %** (e.g. 100% for equal parts flour and water)
- **Desired total weight after feeding**

The app instantly calculates and displays exactly how many grams of **flour** and **water** to add, plus the leftover discard amount (current weight minus what stays in the jar). Show all three output values clearly — Add Flour, Add Water, and Discard — updating in real time as the user types. Include a simple preset button row for common feeding ratios (1:1:1, 1:2:2, 1:5:5) that auto-fills the inputs. Keep the UI clean and readable on mobile — a baker's hands might be floury.