---
epic: 8
story: 8.7
title: "Windows Theming"
status: draft
---

## Epic 8 — Windows App (Rust + iced)
**Goal:** Fast, lightweight native Windows app -- single .exe, no runtime dependencies.

### Story 8.7: Windows Theming

As a **Windows user**,
I want CalcPad to match the Windows system theme including dark/light mode and accent colors,
So that the app looks like a native Windows 11 application.

**Acceptance Criteria:**

**Given** Windows is set to Light mode
**When** CalcPad launches
**Then** the app renders with a light theme

**Given** Windows is set to Dark mode
**When** CalcPad launches
**Then** the app renders with a dark theme

**Given** the system theme changes while CalcPad is running
**When** the registry key for `AppsUseLightTheme` changes
**Then** CalcPad detects the change and transitions to the new theme without restart

**Given** the user has a custom accent color set in Windows Settings
**When** CalcPad renders interactive elements (selections, focused borders, buttons)
**Then** the system accent color is used for those elements

**Given** the app is running on Windows 11
**When** the window renders
**Then** the custom iced theme approximates the Mica or Acrylic material design where feasible (or uses a flat theme that harmonizes with Windows 11 aesthetics)

**Given** the app is running on Windows 10
**When** the window renders
**Then** the theme degrades gracefully (no Mica/Acrylic, but still matches light/dark mode)