# Handoff: Helder — editor for working with Claude Code

## Overview

Helder is a desktop code editor built around one job: work on a codebase together with
Claude Code. It replaces a general IDE with four columns — source control, explorer,
editor, agent — plus five overlays (search, keyboard shortcuts, project note, project
launcher, expanded diff) and a set of small surfaces (context menus, a pass-on-to-agent
prompt, tooltips, a markdown preview).

This handoff describes one consistent visual system for all of those screens.

## About the design files

The files in this bundle are **design references written in HTML**. They show the
intended look, spacing and states. They are not production code to copy.

The task is to **recreate these screens in the target codebase's own environment**
(Electron + React, Tauri + Svelte, SwiftUI, whatever the app already uses) with its
established patterns. If no environment exists yet, pick the framework that fits a
desktop editor and implement the design there.

`Helder IDE.dc.html` is a single-canvas board: every screen sits on one page, side by
side, at real pixel sizes. Open it in a browser to inspect any value with devtools.

## Fidelity

**High fidelity.** Colours, type, row heights, paddings, radii and states are final and
exact. Recreate them pixel-for-pixel. Everything is authored with inline styles so any
element's computed value can be read directly from the file.

Two things are deliberately *not* final:
- The code shown inside the editor panes is sample content, not a spec.
- Icons are Unicode stand-ins (`⌕ ▤ ◇ ⧉ ✎ ↺ ⇄ ⑂ ◆ →`). Ship them as Lucide glyphs at
  stroke width 1.75, 16px inline / 18px standalone.

---

## Design tokens

### Surfaces (four, no more)

| Token | Hex | Use |
|---|---|---|
| `editor` | `#101720` | Editor canvas, terminal, launcher backdrop, code blocks |
| `panel` | `#18202B` | Title bar, side panels, status bar, overlays, menus, tooltip host |
| `raised` | `#232C39` | Selected row, hairline borders, tooltip surface, keycap borders |
| `hover` | `#1E2733` | Row hover fill only |

### Text on dark

| Token | Hex | Use |
|---|---|---|
| `text-1` | `#F4F5F4` | Active file, dialog titles, selected row |
| `text-2` | `#E4E7E6` | Body copy, code plain text |
| `text-3` | `#BAC0C0` | Inactive rows, identifiers, secondary copy |
| `text-4` | `#6C7783` | Labels, paths, meta, comments |
| `text-5` | `#3A424C` | Line numbers, disabled |

### Accent — amber, reserved

`#E8913A` primary · `#C4741F` deep · `#F0B476` soft · `rgba(232,145,58,.10)` tint ·
`rgba(232,145,58,.22)` focus ring.

Amber is allowed **only** for: the active toolbar toggle (tint fill), the 2px selection
rule, the caret, keycap glyphs, the blinking period in the wordmark, the primary button
fill (ink text on amber, never white), the search-hit highlight, section markers, list
markers, links, and counts in the status bar. Never an amber panel, never an amber
heading.

### Light canvas (this board only)

`#EFF0EE` page · `#E5E7E4` spec card · `#CDD1CD` hairline · `#171C22` ink ·
`#3A424C` ink muted · `#6B7480` ink dim. The application itself is dark only.

### Syntax — six colours, all muted

| Role | Hex |
|---|---|
| plain / function name | `#E4E7E6` |
| variable / property | `#BAC0C0` |
| comment | `#6C7783` |
| keyword / operator / pseudo-class | `#C3A6CE` |
| string / value / type path | `#8FBFB4` |
| number / tag / hex literal | `#F0B476` |

No bold, no italic in code. Weight stays 400 so the column reads flat.

### Diff

- added: text `#8FBFB4`, fill `rgba(143,191,180,.12)`, 2px left rule `#8FBFB4`
- removed: text `#C4741F`, fill `rgba(196,116,31,.14)`, 2px left rule `#C4741F`
- counts in headers: `+1` in `#8FBFB4`, `−1` in `#C4741F` (real minus sign U+2212)

No green, no red anywhere. The diff reads on shape and on the 2px rule.

### Type

- `IBM Plex Mono` — 400/500/600/700. All labels, paths, code, keycaps, titles, numbers.
- `IBM Plex Sans` — 400/500. Rows, menu items, tooltips, buttons, running text.

| Role | Spec |
|---|---|
| Board display | Mono 700, 58px/1.02, `-0.04em` |
| Section title | Mono 700, 20px/1.2, `-0.02em` |
| Dialog title | Mono 700, 14px/1 |
| Section/panel label | Mono 700, 10px, `0.14em`, uppercase, `#6C7783` |
| Board label | Mono 700, 10–11px, `0.14em`, uppercase, `#6B7480` |
| Code | Mono 400, 13px / 20px line box |
| Search hit line | Mono 400, 12px / 24px line box |
| Path / meta / status bar | Mono 400, 11–12px |
| Keycap | Mono 600, 12px, padding 4px 6px, 1px `#232C39`, radius 2px, glyph `#E8913A` |
| Row label | Sans 400 13px (500 when selected) |
| Body copy | Sans 400, 14px/1.7, max 68ch |
| Tooltip | Sans 400, 12px/1.5 |

### Geometry

| Value | Where |
|---|---|
| 24px | Explorer / launcher-adjacent row height |
| 26px | Source-control row height |
| 28px | Status bar, state-specimen rows |
| 30px | Context-menu item height |
| 34px | Editor tab strip, markdown/code panel header |
| 44px | Title bar and toolbar |
| 20px | Code line box (13px type) |
| 2px | Radius: buttons, inputs, tags, keycaps, menus' inner rows, code blocks |
| 4px | Radius: panels, cards, menus |
| 8px | Radius: overlays (modals) only |
| 1px | Every hairline (`#232C39` on dark, `#CDD1CD` on light) |
| 2px | Accent rule: selection, focus border, pull-quote |
| 9999px | Traffic-light dots and avatars only |

Column widths in the workspace: source control 236 · explorer 288 · editor flex ·
agent 480. Agent terminal block 190px tall. Full frame 1760 × 1000.

### Elevation

Only two shadows exist:
- dropdown / context menu: `0 4px 16px rgba(23,28,34,.10)`
- overlay: `0 16px 48px rgba(23,28,34,.18)`

No ambient card shadow, no glow.

### Motion

Colour transitions only, 160ms `cubic-bezier(0.22,1,0.36,1)` (120ms on small controls).
The single exception is `blink`: a stepped 1.1s on/off (no fade) used for the caret, the
terminal block cursor and the amber period in the wordmark. No entrance animation, no
lift, no scale, no parallax.

---

## Screens

### 01 · Workspace (1760 × 1000)

Vertical stack: title bar 44px → body (flex row) → status bar 28px.

**Title bar** (`#18202B`, 1px bottom `#232C39`, padding 0 14px, gap 18px)
Traffic lights 12px (`#E8913A`, `#6C7783`, `#3A424C`, gap 8px) · wordmark
`helder` Mono 700 13px `#F4F5F4` with a blinking `.` in `#E8913A` · project `odynt`
Mono 12px `#6C7783` · `·` · branch `main` Mono 500 12px `#E8913A` · breadcrumb of the
open path in Mono 12px `#6C7783`, last segment `#F4F5F4` 600, `›` separators · then the
toolbar, right-aligned, gap 4px.

Toolbar toggle: label Sans 12px + keycap. Off = label `#BAC0C0`, no fill. On = fill
`rgba(232,145,58,.10)`, label `#F4F5F4` 500, keycap border `rgba(232,145,58,.35)`.
Hidden-files-off is the muted case: label and keycap both `#6C7783`. Toggles:
Search ⌘F · Auto-fit ⌘A · Hidden ⌘. · Note ⌘N · Git ⌘G · `?` (26px square, 1px border).

**Source control column** (236px, `#18202B`, 1px right border)
Commit box: 52px `#101720` field, 1px `#232C39`, radius 2, placeholder
"Shift+Enter to commit" `#6C7783`; 34px push button `↑` beside it, same border.
Group header: Mono 700 10px `0.14em` uppercase `#6C7783`, count right in `#E8913A`
("STAGED CHANGES 4", "CHANGES 1"). Rows 26px: status letter (Mono 600 10px — staged
`#8FBFB4`, unstaged `#F0B476`) · 8px type badge · file name Sans 12px, ellipsised.
Footer line "4 staged · 1 unstaged" Mono 11px `#6C7783`.

**Explorer** (288px, `#18202B`) — 30px header ("EXPLORER" / project name), then 24px
rows. Indent 16px per level (12 · 28 · 44 · 60 · 76 padding-left). Collapsed `›`
`#6C7783`; expanded `⌄` `#E8913A`, its label `#F4F5F4`. File rows carry an 8px type
badge and, when dirty, a trailing `M` in `#8FBFB4`.

Type badge: Mono 600 8px, ink text `#101720` on a per-extension fill, radius 2,
padding 3px 4px — php `#C3A6CE` · md `#BAC0C0` · js `#F0B476` · css `#8FBFB4`.

**Editor** (flex, `#101720`) — 34px strip: "MODIFIED" label, `+1` / `−1` counts, then a
right-aligned segmented control (1px `#232C39`, radius 2, dividers 1px): Actual ·
Original · Diff · Split. Active segment = amber fill with `#171C22` text.
Code area: CSS grid `56px 1fr`, line box 20px, numbers right-aligned `#3A424C` with
14px right padding. **Indentation is padding-left on the code cell** (7.82px per space:
31.3 / 62.6 / 93.8 / 125.1) — do not ship non-breaking spaces.

**Agent panel** (480px, `#18202B`, 1px left border)
Header: 60px `#232C39` square (mark), then `Claude Code` Mono 700 14px + version in
`#6C7783`, model line Sans 12px `#BAC0C0`, cwd Mono 12px `#6C7783`.
Notice strip: fill `rgba(232,145,58,.10)`, `[ ! ]` Mono 600 12px `#E8913A`, sentence
Sans 12px, inline command in Mono `#F0B476`.
Transcript: user turn prefixed `›` in `#E8913A`, agent turn `◆` in `#6C7783`, text
Sans 13px/1.6. Tool calls sit in a `#101720` block, 1px `#232C39`: verb in `#8FBFB4`
(read) or `#F0B476` (write), target and counts `#6C7783`.
Prompt field: 44px, `#101720`, **2px `#E8913A` border + `0 0 0 2px rgba(232,145,58,.22)`
ring** (this is the focus treatment everywhere), `›` prefix, blinking 1px caret.
Status line: Mono 11px `#6C7783`; project chip = amber fill with `#171C22` text;
`▸▸ auto mode` in `#E8913A`; slash hint right.
Terminal: 190px, `#101720`, Mono 12px/1.7 — `[main]` `#8FBFB4`, `[~/path]$` `#6C7783`,
output `#6C7783`, 7×14px blinking amber block cursor.

**Status bar** (28px, `#18202B`) — `⑂ main` in `#E8913A`, `+16` `#8FBFB4`, `−12`
`#C4741F`, then right-aligned path · Ln/Col · UTF-8 · LF · language (`#BAC0C0`).

### 02a · Search (⌘F)

Overlay: flat ink scrim `rgba(16,23,32,.72)` (no blur), 34px inset, panel `#18202B`,
1px `#232C39`, radius 8, overlay shadow.

- Query bar 54px: `⌕` `#E8913A`, query Mono 500 16px `#F4F5F4`, blinking caret; right
  side = extension filters (active = amber fill + ink text; inactive = 1px border,
  `#BAC0C0`) and a Mono 11px result summary `#6C7783` behind a 1px left divider.
- Three columns: **this file** (230px) · **project** (flex) · **files** (250px), split by
  1px borders. Column headers are the standard 10px mono labels; the focused column's
  header is `#E8913A` with a count chip (amber fill, ink text).
- Result group header: type badge + path Mono 12px `#BAC0C0`, hit count right `#6C7783`.
- Hit lines: grid `64px 1fr`, line box 24px. Match run = amber fill with `#171C22` text
  on the selected row, `#F0B476` text elsewhere. Selected row: `#232C39` fill, 2px amber
  left rule, and the line number lifts to `#E8913A` (never leave it at `#3A424C`).
- Empty column state: one plain sentence, Sans 12px `#6C7783` ("No matches in this
  file." / "No file names match."). No illustration.
- Footer 38px: key hints (`⌘←`/`⌘→` column, `⌘↑`/`⌘↓` row, `↵` open) with amber glyphs,
  `esc` chip right.

### 02b · Keyboard shortcuts (`?`)

Same overlay shell. 50px header with `◇` `#E8913A` + "Keyboard shortcuts" + `esc` chip.
Body groups (`NAVIGATE`, `AGENT`, `GIT`, `FILE`) each a 10px mono label, then a
`92px 1fr` grid: keycap cluster left (gap 4px), description Sans 13px `#E4E7E6` right,
6px vertical padding per row.

### 02c · Project note (⌘N)

Same shell. Header: `▤` amber, "Note", filename `.notes.txt` Mono 12px `#6C7783`, then
the primary button — amber fill, `#171C22` text, Sans 500 12px, radius 2, padding
6px 10px, with a `⌘P` keycap at Mono 600 11px — then the `esc` chip.
Body: Mono 400 14px/1.7 `#E4E7E6`, max 68ch, 18px between paragraphs, blinking caret at
the end of the text. Footer 34px: "saved on focus loss · 412 characters".

The note is plain text and it is the agent's input: ⌘P sends the whole note.

### 02d · Project launcher

Window `#101720` with only traffic lights (34px), no title bar. Centred panel on
`#18202B`, radius 8, overlay shadow, top-aligned with 20px/40px padding.
Header: `◆` amber + wordmark with blinking period + "Open a project to begin" Sans 12px
`#6C7783`. Then a 46px "Open new project…" row with `+` amber and an `↵` chip.
`RECENT` label, then 38px rows: `▤` icon, name Sans 500 13px, path Mono 11px `#6C7783`.
Selected row: `#232C39`, 2px amber left rule, icon and path lift one step.
Footer 36px: `⌘↑↓ navigate · ↵ open`.

### 03 · Expanded diff (1760 × 620)

Own window: 42px title bar (traffic lights, path Mono 500 12px `#F4F5F4`, "MODIFIED",
`+1` / `−1`, "staged → actual" Mono 11px `#6C7783`, and a right-aligned
"Collapse `esc`" button with 1px border).
Two panes split by a 1px border; each has a 30px header — left `ORIGINAL` + "before"
`#3A424C`, right `UPDATED` in `#E8913A` + "after".
Panes are grids `52px 1fr`, line box 22px, indentation as padding-left, and **identical
line numbering in both panes** so the eye can travel across. Changed row gets the fill,
the 2px left rule and a lifted number colour.

### 04 · Small surfaces

**Context menu** (explorer and source control) — 320px, `#18202B`, 1px `#232C39`,
radius 4, dropdown shadow, 8px vertical padding. First a path header (Mono 11px
`#6C7783`, 1px bottom border). Items 30px, Sans 13px `#BAC0C0`, icon `#6C7783`.
Highlighted item: `#232C39` fill, 2px amber left rule, label `#F4F5F4` 500, icon amber.
Destructive item ("Delete file", "Discard changes"): `#C4741F` label. Groups separated
by a 1px rule with 6px margins.

Explorer items: Pass on reference · Copy reference · Pass on file name · Copy file name
| Rename file · Show in Finder · Delete file.
Source-control items: Pass on reference · Copy reference | Stage changes · Open diff ·
Discard changes.

**Pass on to agent** — 460px panel, 14px padding, gap 12. Title row (`◇` amber +
Mono 700 13px + `esc` chip), a focused 38px input (2px amber border + ring, blinking
caret), then an INSERTS preview: 10px mono label + the composed string on an amber fill
with `#171C22` text, radius 2, ellipsised. Footer hint `↵ insert into agent · esc cancel`
with amber glyphs.

**Tooltip** — `#232C39` surface, 1px `#3A424C`, radius 2, padding 8px 10px, max 300px,
Sans 12px/1.5 `#E4E7E6`. No arrow, no shadow. The current state is named inside the
sentence in amber ("Hidden files: *hidden* — …", "Auto-fit panels: *on* — …"), then one
sentence saying what a click does.

**Markdown Actual / Preview** — same 34px header on both halves; the segmented control's
active side is the amber fill. Actual = the code grid (`44px 1fr`, line box 20px) with
`##` headings in `#F0B476`. Preview: 18px/20px padding, max 68ch, Sans 13px/1.7 body,
Mono 700 headings with a 1px `#232C39` underline.

### 06 · Code colours and markdown preview

Four specimens at 620px: a JS module, a PHP class, a CSS file and the full markdown
preview. Each panel: 34px header with type badge, path Mono 500 12px, and a right
language label (or the Actual/Preview control).

The markdown preview is the reading surface, so it is the one place where Sans body copy
gets room:
- eyebrow: 10px mono label `#6C7783`
- h2: Mono 700 24px/1.1, `-0.03em`, `#F4F5F4`
- h3: Mono 700 17px/1.2 with a 1px `#232C39` underline, 8px below the text
- paragraph: Sans 14px/1.7 `#E4E7E6`, max 68ch, `text-wrap: pretty`
- list: flex rows, gap 10, `—` marker in `#E8913A` (never a bullet, never an emoji)
- inline code: Mono 13px `#F0B476` on `#18202B`, 1px `#232C39`, radius 2, padding 1px 5px
- block quote: 2px amber left rule, 16px left padding, Sans *italic* 15px `#F0B476`
- code block: `#18202B`, 1px `#232C39`, radius 2, padding 14px 16px, Mono 13px/20px,
  syntax palette as above
- table: 1px `#232C39` container, radius 2; header row on `#18202B` with 10px mono
  labels; body rows Sans 13px `#BAC0C0`, cells 10px 14px, 1px row rules; state words use
  `#8FBFB4` (done) and `#E8913A` (open)
- link: `#E8913A` with a 1px `#232C39` bottom border; hover lifts the text to `#F4F5F4`
  and the border to `#E8913A`. `→` marks forward action.

---

## Interactions and behaviour

| Trigger | Result |
|---|---|
| `⌘F` | Search overlay, query seeded from the editor selection |
| `⌘↑` / `⌘↓` | Move the row cursor in the focused list |
| `⌘←` / `⌘→` | Move focus between search columns |
| `↵` | Open the selected row (search hit, file, recent project) |
| `⌘→` (editor) | Pass the current selection to the agent |
| `⌘M` | Cycle Actual · Original · Diff · Split |
| `⌘C` / `⌘↵` / `⌘P` (git) | Focus commit message / commit staged / push branch |
| `⌘A` | Toggle auto-fit panels (columns re-fit on resize and focus) |
| `⌘.` | Toggle hidden dotfiles in tree and search |
| `⌘G` | Show or hide the source-control column |
| `⌘S` / `⌘W` / `⌘D` | Save / close / delete (confirm) the current file |
| `⌘N` | Open the project note; it saves on focus loss |
| `⌘P` (note open) | Send the whole note to the agent |
| right-click a row | Context menu, anchored to the pointer, first item pre-highlighted |
| `esc` | Close the top overlay, menu or prompt; never more than one |

Rules that hold everywhere:
- Exactly one overlay at a time, on a flat ink scrim. Overlays never stack.
- Hover changes fill one step and nothing else. No lift, no scale, no shadow, no opacity.
- Press holds the hover colour. Nothing shrinks.
- Focus is always the 2px amber border plus the 2px 22% ring. Never remove it.
- Disabled is 40% opacity plus `cursor: not-allowed`, no recolouring.
- Empty and error states are one plain sentence starting with an em dash. No icon, no
  apology, no exclamation mark.

## State

- `project` — path, branch, recent list (persisted)
- `openFile` — path, language, dirty flag, cursor line/col, view mode
  (`actual|original|diff|split`)
- `tree` — expanded paths, selected path, `showHidden`
- `git` — staged[], unstaged[], commit message draft, ahead/behind counts
- `agent` — model, session, transcript, prompt draft, pending tool calls, auth notices
- `overlay` — `null | search | shortcuts | note | diff | launcher | menu | passOn`
- `panels` — column widths, `autoFit`, `gitVisible`
- `note` — text, dirty flag (write on blur)

Search runs per keystroke against three indexes (open file, project contents, file
names) and reports counts per column; a query with no hits leaves the columns in their
empty state rather than collapsing them.

## Assets

None. No images, no illustrations, no photography. Icons come from Lucide
(`lucide@0.544.0`, stroke width 1.75); the Unicode glyphs in the mock are placeholders.
Fonts are IBM Plex Mono and IBM Plex Sans (currently from Google Fonts — swap in local
woff2 for a desktop build).

## Files

- `Helder IDE.dc.html` — the design board: all screens, one canvas, real sizes
- `tokens/*.css` — the Kade token files the board is built on (colour, type, spacing,
  radius, elevation, motion, fonts)
- `styles.css` — the token entry point

Open `Helder IDE.dc.html` in a browser; the board is inert (no interaction) by design.