diff --git a/.memory/state.md b/.memory/state.md
index ab8a5cf..ccb6647 100644
--- a/.memory/state.md
+++ b/.memory/state.md
@@ -1,9 +1,8 @@
 # State
 - Core engine: `src/rpn-calculator.js`
-- Active demo: `samples/calc-02/` portrait-only HP48GX layout; display-adjacent button row stays in 4 columns and now shares the same base button styling as the function keys
-- Mode button shows the current angle mode only; selecting a mode uses a popup menu
+- Default demo: `samples/dev/` classic browser demo; `samples/calc-02/` remains the portrait-first HP48GX-inspired reference
 - Public API: `push`, `pop`, `clear`, `swap`, `remove`, `edit`, `isValidIndex`, `input`, `command`, `getOperationsByCategory`, `getConstants`, `listConstants`, `setConstant`, `removeConstant`, `hasConstant`
 - Config: `maxSize`, `base`, `angleMode`, `enabledCommands`
-- Commands: arithmetic, stack, trigonometry, constants `pi`, `e`, `phi`, `g`, and `c`; arithmetic now includes `root` for y-th roots; constants can now be added or removed dynamically through the core API
-- Demo actions: keyboard focus is kept on the hidden input on desktop so typing keeps working; the keypad layout places Enter in the bottom-left, ± in the former Enter position, and Esc before Clear for safety; paste parses clipboard text as a number before pushing it to the stack; Ctrl+V is supported via the hidden input paste event; backspace is ignored when the stack is empty; operation errors are shown as an overlay bar on top of the calculator with a shorter timeout and darker red; the display button row uses a 4-column grid with a spacer cell to preserve alignment
+- Commands: arithmetic, stack, trigonometry, constants `pi`, `e`, `phi`, `g`, and `c`; arithmetic includes `root` with `y√x`, `yroot`, and `nroot` aliases; constants can be added or removed dynamically through the core API
+- Demo behavior: `samples/dev/` keeps hidden input focus on desktop and supports clipboard paste; `samples/calc-02/` uses compact mode/constants popups, a 4-column display-adjacent row, stack selection/move mode, and paste through the hidden input
 - Exports: browser `window.RpnCalculator`, CommonJS `module.exports`
diff --git a/README.md b/README.md
index 864fed1..7cedfbd 100644
--- a/README.md
+++ b/README.md
@@ -1,15 +1,16 @@
 # RPN Virtual Calculator
 
-A browser-friendly RPN calculator built around a small, generic JavaScript API.
+A browser-friendly RPN calculator built around a small JavaScript API.
 
 ## Overview
 
 This project provides:
 
 - a reusable JavaScript RPN engine in `src/rpn-calculator.js`
-- browser demos in `samples/dev/` and `samples/calc-02/`
-- a command system centralized in a single operation dictionary
-- a small public API focused on stack operations and generic command dispatch
+- a classic browser demo in `samples/dev/`
+- a portrait-first HP48GX-inspired demo in `samples/calc-02/`
+- a centralized command system with aliases
+- a compact public API focused on stack operations, editing, and command dispatch
 
 The main class is `RpnCalculator`.
 
@@ -19,9 +20,6 @@ The main class is `RpnCalculator`.
 - `samples/dev/index.html`: browser demo entry point
 - `samples/dev/index.css`: demo styles
 - `samples/dev/index.js`: demo UI and keyboard logic
-- `samples/calc-01/index.html`: active browser demo entry point
-- `samples/calc-01/index.css`: demo styles
-- `samples/calc-01/index.js`: demo UI and keyboard logic
 - `samples/calc-02/index.html`: portrait-first HP48GX-style demo entry point
 - `samples/calc-02/index.css`: portrait-first demo styles
 - `samples/calc-02/index.js`: portrait-first HP48GX-style demo UI and keyboard logic
@@ -68,10 +66,10 @@ State exposed on instances:
 
 ```js README.md
 const calc = new RpnCalculator({
-  maxSize: 2048,
-  base: 10,
-  angleMode: 'deg',
-  enabledCommands: ['add', 'sub', 'mul', 'div']
+	maxSize: 2048,
+	base: 10,
+	angleMode: 'deg',
+	enabledCommands: ['add', 'sub', 'mul', 'div']
 });
 ```
 
@@ -88,6 +86,9 @@ Available constants:
 
 - `pi`
 - `e`
+- `phi`
+- `g`
+- `c`
 - plus any user-defined constants added through the engine API
 
 They can be used through `command(...)`:
@@ -194,10 +195,10 @@ console.log(calc.pop()); // 5
 ```html README.md
 <script src="./src/rpn-calculator.js"></script>
 <script>
-  const calc = new RpnCalculator({ angleMode: 'deg' });
-  calc.push(9);
-  calc.command('sqrt');
-  console.log(calc.pop());
+	const calc = new RpnCalculator({ angleMode: 'deg' });
+	calc.push(9);
+	calc.command('sqrt');
+	console.log(calc.pop());
 </script>
 ```
 
@@ -239,7 +240,7 @@ console.log(calc.pop()); // 0.5
 
 ## Demo
 
-The active demo lives in `samples/dev/`.
+The default demo lives in `samples/dev/`.
 
 Main UI features:
 
@@ -249,7 +250,7 @@ Main UI features:
 - angle mode selector for `deg`, `rad`, and `grad`
 - status pills for `inputValue` and `isEditing`
 - grouped panels for `Stack`, `Arithmetic`, `Trigonometry`, and `Constants`
-- error display area
+- keyboard-friendly hidden input on desktop
 
 ## Calc 02 demo
 
diff --git a/README.tmp.md b/README.tmp.md
new file mode 100644
index 0000000..7cedfbd
--- /dev/null
+++ b/README.tmp.md
@@ -0,0 +1,289 @@
+# RPN Virtual Calculator
+
+A browser-friendly RPN calculator built around a small JavaScript API.
+
+## Overview
+
+This project provides:
+
+- a reusable JavaScript RPN engine in `src/rpn-calculator.js`
+- a classic browser demo in `samples/dev/`
+- a portrait-first HP48GX-inspired demo in `samples/calc-02/`
+- a centralized command system with aliases
+- a compact public API focused on stack operations, editing, and command dispatch
+
+The main class is `RpnCalculator`.
+
+## Project structure
+
+- `src/rpn-calculator.js`: calculator engine
+- `samples/dev/index.html`: browser demo entry point
+- `samples/dev/index.css`: demo styles
+- `samples/dev/index.js`: demo UI and keyboard logic
+- `samples/calc-02/index.html`: portrait-first HP48GX-style demo entry point
+- `samples/calc-02/index.css`: portrait-first demo styles
+- `samples/calc-02/index.js`: portrait-first HP48GX-style demo UI and keyboard logic
+- `samples/calc-XX/`: placeholder name for future demo variants
+
+## Public API
+
+The calculator API is centered on these methods:
+
+- `push(value)`
+- `pop()`
+- `clear()`
+- `swap(index1, index2)`
+- `remove(index)`
+- `edit(index)`
+- `isValidIndex(index)`
+- `input(command)`
+- `command(name, ...args)`
+
+Instance helpers also available:
+
+- `getOperationsByCategory()`
+- `getConstants()`
+- `listConstants()`
+- `setConstant(name, value)`
+- `removeConstant(name)`
+- `hasConstant(name)`
+
+Static helpers also available:
+
+- `RpnCalculator.getOperationCategories()`
+- `RpnCalculator.getOperationsByCategory()`
+
+State exposed on instances:
+
+- `inputValue` as a string
+- `isEditing` as a boolean
+- `stack` as the current internal stack array used by the demo
+- `angleMode`
+- `base`
+- `maxSize`
+
+## Constructor options
+
+```js README.md
+const calc = new RpnCalculator({
+	maxSize: 2048,
+	base: 10,
+	angleMode: 'deg',
+	enabledCommands: ['add', 'sub', 'mul', 'div']
+});
+```
+
+Supported options:
+
+- `maxSize`: maximum stack size, default `2048`
+- `base`: numeric base, default `10`, accepted range `2..16`
+- `angleMode`: `deg`, `rad`, or `grad`, default `deg`
+- `enabledCommands`: optional whitelist of enabled commands and aliases
+
+## Constants
+
+Available constants:
+
+- `pi`
+- `e`
+- `phi`
+- `g`
+- `c`
+- plus any user-defined constants added through the engine API
+
+They can be used through `command(...)`:
+
+```js README.md
+calc.command('pi');
+calc.command('e');
+```
+
+## Supported commands
+
+### Stack
+
+- `enter`
+- `dup`
+- `drop`
+- `swap`
+- `clear`
+
+### Arithmetic
+
+- `add` alias: `+`
+- `sub` alias: `-`
+- `mul` alias: `*`
+- `div` alias: `/`
+- `mod` alias: `%`
+- `pow` aliases: `^`, `y^x`
+- `root` aliases: `y√x`, `yroot`, `nroot`
+- `sqr`
+- `neg`
+- `sqrt` alias: `sqrt(x)`
+- `recip` alias: `1/x`
+- `log`
+- `ln`
+
+### Trigonometry
+
+- `sin`
+- `cos`
+- `tan`
+- `asin`
+- `acos`
+- `atan`
+
+## Behavior notes
+
+- `mod` is a percentage operator:
+  - `a b % => (a * b) / 100`
+- `pow` accepts aliases `^` and `y^x`
+- `sqrt` accepts alias `sqrt(x)`
+- `recip` accepts alias `1/x`
+- `div` and `recip` throw `Division by zero` when needed
+- `root` computes the y-th root as `x^(1/y)` and throws `Invalid input for root` for invalid inputs
+- `sqrt` throws `Invalid input for sqrt` for negative values
+- `asin` and `acos` throw explicit domain errors outside `[-1, 1]`
+- `log` throws `Invalid input for log` for values `<= 0`
+- `ln` throws `Invalid input for ln` for values `<= 0`
+- `log` uses `Math.log10`
+- `ln` uses `Math.log`
+- direct trigonometric functions convert input using `toRadians(...)`
+- inverse trigonometric functions convert results back using the current angle mode
+- `angleMode` supports `deg`, `rad`, and `grad`
+- formatted numeric values are rounded to 12 decimal places
+- `-0` is normalized to `0`
+- `inputValue` remains a string to preserve future non-decimal input support
+- base 10 input is parsed with `Number(...)`
+- non-decimal input currently uses `parseInt(..., base)`
+
+## Input handling
+
+`input(command)` supports two modes:
+
+- single-character editing input
+- command dispatch
+
+Accepted single-character editing input currently includes:
+
+- `0-9`
+- `A-F`
+- `a-f`
+- `+`
+- `-`
+- `.`
+
+Everything else is forwarded to `command(...)`.
+
+## Basic usage
+
+### CommonJS
+
+```js README.md
+const RpnCalculator = require('./src/rpn-calculator');
+
+const calc = new RpnCalculator();
+calc.push(2);
+calc.push(3);
+calc.command('add');
+
+console.log(calc.pop()); // 5
+```
+
+### Browser
+
+```html README.md
+<script src="./src/rpn-calculator.js"></script>
+<script>
+	const calc = new RpnCalculator({ angleMode: 'deg' });
+	calc.push(9);
+	calc.command('sqrt');
+	console.log(calc.pop());
+</script>
+```
+
+### Editing values through `input(...)`
+
+```js README.md
+const calc = new RpnCalculator();
+
+calc.input('1');
+calc.input('2');
+calc.input('.');
+calc.input('5');
+calc.command('enter');
+
+console.log(calc.pop()); // 12.5
+```
+
+### Aliases
+
+```js README.md
+const calc = new RpnCalculator();
+calc.push(6);
+calc.push(7);
+calc.command('+');
+console.log(calc.pop()); // 13
+```
+
+### Constants and trigonometry
+
+```js README.md
+const calc = new RpnCalculator({ angleMode: 'deg' });
+calc.command('pi');
+console.log(calc.pop());
+
+calc.push(30);
+calc.command('sin');
+console.log(calc.pop()); // 0.5
+```
+
+## Demo
+
+The default demo lives in `samples/dev/`.
+
+Main UI features:
+
+- four visible stack lines
+- main display/status area
+- visible angle mode indicator
+- angle mode selector for `deg`, `rad`, and `grad`
+- status pills for `inputValue` and `isEditing`
+- grouped panels for `Stack`, `Arithmetic`, `Trigonometry`, and `Constants`
+- keyboard-friendly hidden input on desktop
+
+## Calc 02 demo
+
+`samples/calc-02/` is a portrait-first HP48GX-inspired demo.
+It keeps the display-adjacent button row aligned in four columns, uses compact popup menus for mode and constants, and supports clipboard paste plus the `y√x` root operation.
+
+The demo loads the engine from:
+
+```html README.md
+<script src="../../src/rpn-calculator.js"></script>
+```
+
+### Demo keyboard support
+
+The current demo supports:
+
+- digits and decimal point
+- numpad digits and numpad arithmetic keys
+- `Enter`
+- `Backspace`
+- `Delete`
+- `Escape`
+- `ArrowUp`, `ArrowDown`, `ArrowRight`
+- `+`, `-`, `*`, `/`, `%`, `^`
+- `q`, `n`, `r`, `i`, `g`, `l`, `s`, `c`, `S`, `C`
+- `x`, `y`, `z`, `t`
+
+The demo also implements stack selection and stack-item move mode in its UI layer using the public calculator methods.
+It keeps the calculator screen focused and updates the visible stack window as the selection moves.
+
+## Exports
+
+`RpnCalculator` is exposed in both environments:
+
+- browser: `window.RpnCalculator`
+- CommonJS: `module.exports = RpnCalculator`