Alone

A theme for those who thrive coding alone in the dark.

Alone is a warm, low-luminance dark theme for people who code in dark rooms for hours. Every colour in it — syntax, UI chrome, terminal — has a dominant wavelength between 575 and 611 nm: gold, amber, olive, terracotta, dusty rose. There is no blue, no cyan, no purple, and no white text. Foregrounds sit well below the brightness of a typical dark theme, contrast is tuned with APCA rather than maxed out, and a verifier script fails the build if any of that drifts.

It is not a night-vision instrument (see What it does not do); it is a comfortable place to spend a long night.

Variants

Theme	For	What changes
Alone	The default. A dim-but-not-dark room.	Full palette, italic + bold cues, standard chrome.
Alone Soft	Pitch-black rooms, light-sensitive eyes.	Every syntax colour ~20 % dimmer, backgrounds lifted a notch, gentler contrast (own APCA floors).
Alone Focused	Concentration.	Same code colours; UI chrome muted — badges dimmed, sidebar de-emphasised, borders hidden.
Alone Roman	Astigmatism, or anyone who dislikes italic code.	Standard palette with the italic channel removed; two hexes nudged so the pairs italics used to separate stay separable on colour alone.

Details on each are in Theme Variants.

The Science

The old pitch for this theme was "only wavelengths above 575 nm, so your rods stay dark-adapted." That is a claim about dominant wavelength, and it is true — but it is not the same as a claim about the light, and it is not where the comfort actually comes from. Here is what the palette really does and why it helps.

What "warm-only" means on a screen

A monitor mixes three primaries. Any colour that is not fully saturated lights all three subpixels, including the blue one, no matter what hue it reads as. Alone's saturated golds emit almost nothing short of 540 nm; its neutrals — the body text, operators, punctuation, comments — necessarily do, because a neutral is a mix.

Group (Standard)	Example	Dominant λ	Blue subpixel's share of the light	Rod stimulation per unit luminance, vs white
Neutrals (foreground, operators, punctuation, comments)	`#C8B89A`	577 nm	~23–27 % (white is 33 %)	~85 %
Ambers (types, functions)	`#C08868`	579–588 nm	~11–15 %	~60 %
Saturated golds (numbers, keywords, cursor)	`#C8A040`	578–581 nm	~5–6 %	~55 %
Pure red (not in Alone — reserved for future variants)	`#B00000`	612 nm	~0 %	a few %

Rod figures use the CIE 1951 scotopic curve through a tristimulus approximation and are indicative, not exact. The 2.0.0 retune pulled the bright neutrals' blue-subpixel drive from 37–48 % of full output down to 32–39 % without changing their lightness; it cannot go to zero while they stay readable as neutral text.

The rod curve, for reference

Rod (scotopic) sensitivity V′(λ) peaks at 507 nm, not in the blue:

λ (nm)	Colour	V′(λ)	Where it sits in Alone
450	blue	0.46	no dominant hue here; only the neutrals' blue-subpixel component
480	blue-cyan	0.79	—
507	blue-green	1.00 (peak)	—
540	green	0.65	—
560	yellow-green	0.33	—
575–580	yellow / gold	0.16–0.12	Operators, variables, numbers, keywords, types, strings, comments
590	amber	0.07	Functions (588 nm)
610	orange-red	0.016	Special (611 nm), errors (608 nm)
620–650	red	0.007–0.0007	future red-only variants

Where the benefit actually comes from

Low luminance, unsaturated text. The Standard foreground is L* 75 — roughly half the luminance of white — and nothing in the syntax ladder is brighter than L* 81. Glare, halation and contrast-driven fatigue scale with the luminance and edge contrast of the text, so this is the single biggest lever. (The background being #0C0A09 rather than #000000 — L* 2.8 vs 0 — is cosmetic; it does not reduce halation. Dim text does.)
No blue defocus. The eye focuses 450 nm and 620 nm about 1.5–2 dioptres apart; that is why blue text on black shimmers and blooms for astigmatic and uncorrected eyes. Alone's saturated colours span roughly 540–610 nm (≈ 0.5 D of longitudinal chromatic aberration), and the neutrals carry far less blue than white text. This is the most real optical benefit of a warm palette.
Less melanopic stimulation. The melanopsin (ipRGC) curve peaks near 490 nm, close to the rod curve, so the ratios track the rod column above: the golds deliver about half the melanopic stimulus of white per unit luminance, the neutrals about 85 %. Combined with a lower absolute luminance and an OS warm shift (see Display recommendations) that adds up.
Comfort. Warm, low-chroma light at low luminance is simply easier to sit in for hours. That is subjective, and it is fine for it to be — the numbers above are what makes it defensible.

What it does not do

It does not preserve rod dark adaptation. Reading is foveal, cone-mediated vision; any screen bright enough to read from will reset full dark adaptation, and the neutrals stimulate rods at ~85 % of white per unit luminance. Recovery takes 30–40 minutes regardless of hue. If you need to keep night vision — telescope, cockpit, bridge — you need a red-only palette, which is where the roadmap's Apollo / Max Dark variants sit (see Future Plans).
It does not make the background matter. #0C0A09 is warm so that the UI chrome does not look cold against the palette; that is all.

Lightness spacing (L*)

On calibrated OLED and mini-LED displays subtle colour differences disappear, so each syntax tier gets its own perceptual lightness, computed in CIE L*a*b* against the editor background #0C0A09:

L* 81  ███████████████████████████   Operators
L* 75  █████████████████████████     Variables
L* 72  ████████████████████████      Numbers
L* 68  ███████████████████████       Keywords (bold)
L* 65  ██████████████████████        Types
L* 61  ████████████████████          Functions
L* 58  ███████████████████           Strings (italic)
L* 55  ██████████████████            Special
L* 49  ████████████████              Punctuation
L* 44  ███████████████               Comments (italic)

The ladder is monotonic descending. The warm-only palette can't deliver large gaps across all ten tiers — the whole run from Operators to Comments spans under 40 L*. The largest gaps sit at the top and bottom (Operators→Variables, Special→Punctuation, Punctuation→Comments); the middle tiers run in the 3–4 L* range and rely on font style (italic strings/comments/interfaces/defaultLibrary, bold keywords/escapes) and hue (gold vs olive vs dusty-rose) to carry the differentiation that lightness alone can't. The ladder above is rendered by scripts/verify-palette.mjs from the live theme files (exact per-rung L* and gaps are in its section 1 output); the verifier hard-fails on out-of-order roles and on any adjacent gap below 3 L* or ΔE2000 below 4.

Installation

VS Code Marketplace

Open Extensions (Ctrl+Shift+X / Cmd+Shift+X)
Search for "Alone"
Click Install
Open Command Palette (Ctrl+Shift+P / Cmd+Shift+P)
Select Preferences: Color Theme and choose from:
- Alone — The standard theme
- Alone Soft — Dimmer variant for pitch-black rooms
- Alone Focused — Minimal UI for maximum focus
- Alone Roman — Standard palette, no italics (astigmatism / italic-averse)

From VSIX

Download the latest .vsix from Releases
In VS Code, open Command Palette (Ctrl+Shift+P / Cmd+Shift+P)
Run Extensions: Install from VSIX...
Select the downloaded .vsix file
Reload VS Code when prompted

From Source

git clone https://github.com/crypticpy/alone.git
cd alone && npm ci && npx @vscode/vsce package   # produces alone-<version>.vsix
code --install-extension alone-*.vsix

Recommended Settings

For the full Alone experience, add these to your settings.json:

{
  // Font: a variable monospace at a slightly-lighter-than-regular body weight.
  // fontVariations:true maps fontWeight onto the font's wght axis, so 450 really
  // renders as 450 instead of snapping to the nearest static instance.
  "editor.fontFamily": "'JetBrains Mono Variable', 'JetBrains Mono', monospace",
  "editor.fontSize": 14,
  "editor.fontWeight": "450",
  "editor.fontVariations": true,
  "editor.fontLigatures": false,
  "editor.lineHeight": 1.6,
  "editor.letterSpacing": 0.3,

  // Cursor: solid, no blinking (fewer micro-adaptations)
  "editor.cursorBlinking": "solid",
  "editor.cursorStyle": "block",
  "editor.cursorWidth": 2,

  // Brackets: enable colorization (depth maps to dimness)
  "editor.bracketPairColorization.enabled": true,
  "editor.guides.bracketPairs": "active",

  // Smooth scrolling
  "editor.smoothScrolling": true,
  "workbench.list.smoothScrolling": true,
  "terminal.integrated.smoothScrolling": true,

  // Reduce visual noise (minimap kept as a dim shape — no rendered characters)
  "editor.minimap.enabled": true,
  "editor.minimap.renderCharacters": false,
  "editor.minimap.scale": 1,
  "editor.renderWhitespace": "none",
  "editor.renderLineHighlight": "line",
  "editor.occurrencesHighlight": "singleFile",

  // Semantic highlighting (recommended — the theme styles Pylance / rust-analyzer / TS server tokens)
  "editor.semanticHighlighting.enabled": true,

  // Window: reduce chrome if desired
  "window.titleBarStyle": "custom",
  "window.autoDetectColorScheme": false
}

Bold in the theme (keywords, escapes, errors) is CSS bold — weight 700. VS Code themes cannot set intermediate weights; editor.fontWeight only controls the body text, so with the settings above you get 450 body against 700 keywords.

Display Recommendations

OLED

Brightness: 20–40 % in dark rooms
Enable the pixel brightness limiter / ABL if the panel offers one
The palette's L* 75 foreground stays clear at these brightnesses; you should not need to push it higher

Mini LED

Brightness: 30–50 % in dark rooms
Local dimming: Medium (not Maximum) to reduce blooming
Contrast: 80–90 % to prevent halation

Both

Night Shift / Night Light / f.lux: enable, and set it warm (3000–4000 K). Alone stacks well with an OS warm shift: it removes still more of the neutrals' blue-subpixel light, and because nothing in the palette depends on a cool hue, the theme keeps its contrast where a blue-heavy theme collapses toward gray.
True Tone / auto-brightness: disable for consistency.
The screen is still the brightest thing in a dark room. If your goal is less melanopic light in the evening, the biggest levers are the display's absolute brightness and the OS warm shift; the theme helps on top of those, not instead of them.

Color Palette

Syntax Colors

Element	Hex	Style
Operators	`#D8C8A8`	Normal
Variables	`#C8B89A`	Normal
Numbers	`#DEA64E`	Normal
Keywords	`#C8A040`	Bold
Types	`#BC9858`	Normal
Interface/Type-param	`#BC9858`	Italic
Functions	`#C08868`	Normal
Built-in funcs	`#C08868`	Italic
Strings	`#9A8B60`	Italic
Escapes	`#D4B088`	Bold
Regex / decorators	`#A87878`	Italic
Comments	`#6E665B`	Italic
Errors	`#D46A66`	Bold underline

Bracket Pair Colors

Six warm variants for bracket colorization, ordered by perceptual lightness so depth maps to dimness — the deeper you nest, the dimmer the bracket:

Bright Gold #E0B868 (L* ~77)
Gold #C89868 (L* ~66)
Amber-Brown #B08458 (L* ~58)
Umber #967048 (L* ~50)
Dark Umber #7A5C3C (L* ~41)
Deep Brown #604830 (L* ~33)

Background Hierarchy

#0C0A09  Editor background
#0A0908  Sidebar, panels, title bar
#151311  Widgets, dropdowns
#1E1915  Hover states
#28221C  Active/selected
#352D25  Borders, strong highlights

Theme Variants

Alone is the headline family member — tuned for the mesopic range, where both rods and cones contribute, typical of a dim-but-not-dark room. The three siblings are positioned around it; further along the dark-adaptation continuum the family has room to grow (see Future Plans).

Alone (Standard)

The full-featured theme with balanced contrast for extended coding sessions. Default starting point for most users.

Alone Soft

For pitch-black rooms and light-sensitive eyes. All syntax colours reduced ~20 % in brightness, backgrounds slightly lifted to reduce contrast. Verified against its own, lower APCA floors.

Alone Focused

For concentration. UI chrome is muted — activity-bar badges dimmed, sidebar de-emphasised, borders hidden. Syntax highlighting unchanged. Your code takes centre stage.

Alone Roman

The Standard palette with no italics — for astigmatic readers who find slanted monospace edges fringe, or anyone who simply dislikes italic code. Every rule that Standard sets in italic (comments, strings, docstrings, regex, decorators, interfaces, type parameters, namespaces, *.defaultLibrary, *.async, this/self) is upright here; the only italic left is Markdown *emphasis*, which is the document's own formatting. Bold keywords/escapes/errors are unchanged. Two hexes differ from Standard so the pairs that Standard tells apart with italics stay separable on colour alone under red-green colour-vision deficiency: strings #9A8B60 → #9C8B4A and *.defaultLibrary #B08C50 → #AA884C (both verified ΔE2000 ≥ 5 after protan/deutan simulation). What you give up is the italic-only distinctions — interfaces look like classes, library calls like local ones, async like sync.

Terminal Themes

Matching terminal themes are included in the terminal/ directory:

Terminal	File	Installation
Kitty	`terminal/alone.conf`	Copy to `~/.config/kitty/themes/` and `include themes/alone.conf`
iTerm2	`terminal/alone.itermcolors`	Preferences → Profiles → Colors → Import
Alacritty	`terminal/alone.toml`	Import in your `alacritty.toml` config
Windows Terminal	`terminal/alone-windows-terminal.json`	Add scheme to `settings.json`

All terminal themes use the same warm colour palette. The blue and cyan slots carry no short-wavelength dominant hue: blue is a warm gray (#9C948E) and cyan is the terracotta used for functions (#C08868) — two hues a red-green-deficient reader can still tell apart (ΔE2000 ≥ 10 across all eight normal slots), instead of the two near-identical grays that shipped before 2.0.0. Programs that print blue-on-black (ls, grep, man) stay readable (blue Lc 45 against the terminal background).

The sixteen ANSI slots (as shipped in the VS Code theme and mirrored in the terminal files):

Slot	Hex	L*	Bright slot	Hex	L*
Black	`#0C0A09`	3	BrightBlack	`#6E665B`	44
Red	`#B85450`	48	BrightRed	`#D46A66`	57
Green	`#9A8B60`	58	BrightGreen	`#C4B078`	72
Yellow	`#D4A048`	69	BrightYellow	`#E8B850`	77
Blue	`#9C948E`	62	BrightBlue	`#B2AAA3`	70
Magenta	`#A87878`	55	BrightMagenta	`#C89088`	65
Cyan	`#C08868`	61	BrightCyan	`#CEA284`	70
White	`#C8B89A`	75	BrightWhite	`#EDDCC4`	89

Extension Compatibility

Alone includes custom styling for popular extensions:

GitLens

Git blame annotations styled with warm, subtle colors that don't distract from code.

Error Lens

Inline errors, warnings, and hints use the warm palette:

Errors: Warm red (#D46A66)
Warnings: Amber (#D4A048)
Info: Muted gold (#B89860)
Hints: Olive (#9A8B60)

Indent Rainbow

Add to your settings.json for warm-toned indent guides:

"indentRainbow.colors": [
  "rgba(212, 160, 72, 0.07)",
  "rgba(200, 144, 104, 0.07)",
  "rgba(184, 149, 110, 0.07)",
  "rgba(168, 152, 96, 0.07)",
  "rgba(196, 160, 120, 0.07)",
  "rgba(212, 176, 136, 0.07)"
]

Todo Tree

Add to your settings.json for themed TODO highlights:

"todo-tree.highlights.customHighlight": {
  "TODO": { "foreground": "#D4A048", "background": "#D4A04820" },
  "FIXME": { "foreground": "#D46A66", "background": "#D46A6620" },
  "HACK": { "foreground": "#A87878", "background": "#A8787820" },
  "NOTE": { "foreground": "#9A8B60", "background": "#9A8B6020" }
}

Language Support

Alone includes optimized highlighting for:

JavaScript / TypeScript / JSX / TSX
Python (incl. Pylance semantic tokens: self/cls, magic methods, builtins)
Rust (incl. rust-analyzer: lifetimes, attributes, derives, macros)
Go
HTML / CSS / SCSS
JSON / YAML / TOML
Markdown
Shell / Bash
SQL
Diffs and log files
And more via semantic highlighting

See the samples/ directory for demo files showcasing syntax highlighting.

Accessibility

Contrast (WCAG and APCA)

Key contrast values against the editor background (#0C0A09), WCAG 2.x ratio and APCA (0.0.98G-4) Lc side by side:

Element	Color	WCAG	WCAG level	APCA Lc
Operators	`#D8C8A8`	12.0:1	AAA	74
Variables	`#C8B89A`	10.1:1	AAA	65
Numbers	`#DEA64E`	9.1:1	AAA	60
Keywords	`#C8A040`	8.1:1	AAA	54
Types	`#BC9858`	7.3:1	AAA	49
Functions	`#C08868`	6.6:1	AA	45
Strings	`#9A8B60`	5.9:1	AA	40
Comments	`#6E665B`	3.5:1	AA (large)	23

APCA Lc ≥ 60 is the body-text target, ≥ 45 large text, ≥ 30 the floor for non-essential text; comments intentionally sit lower to de-emphasise them. All primary code elements meet WCAG AA for normal text; five of eight clear AAA. The verifier enforces per-role APCA floors (identifiers ≥ 60, syntax ≥ 40, Special/Strings ≥ 37, punctuation ≥ 28, comments ≥ 22; Alone Soft has its own lower floors) as hard failures, and this table is rendered by node scripts/verify-palette.mjs --write-readme.

Colour-vision deficiency

A warm-only palette lives mostly on the red-green axis, which is exactly what protanopes and deuteranopes lose. So the verifier simulates protan and deutan vision for every variant and requires that ten role pairs that carry meaning (types vs functions, functions vs strings, keywords vs types, numbers vs keywords, strings vs special, errors vs functions/special, escapes vs variables, defaultLibrary vs types, variables vs parameters) stay at least ΔE2000 5 apart after simulation — or differ in font style. Alone Roman has no italic cue, so it passes on colour alone (that is why two of its hexes differ from Standard). The eight normal ANSI slots (0–7) must stay ≥ ΔE2000 10 apart pairwise; the bright slots (8–15) are deliberately the same hues one step lighter, so they are not held to that bound against their dim twins. All four variants pass; the exact numbers are in the verifier's sections 4 and 5.

Astigmatism

Body text at L* 75 rather than white, and nothing brighter than L* 81 in the syntax ladder — halation scales with text luminance
No blue, so no blue defocus / chromatic fringing on dark backgrounds
Body weight 450 via editor.fontWeight + editor.fontVariations (see settings); bold stays a plain 700
Cursor uses mid-tier gold (#D4A048) rather than the brightest palette hex — a small bright point on near-black is a halation hotspot, so we keep it dimmer
Alone Roman removes the italic channel; Alone Soft lowers contrast further

Italics

Italics provide cheap differentiation (strings, comments, interfaces, type parameters, defaultLibrary, regex) within the warm palette. But slanted edges in a monospace font can increase fringing for astigmatic readers. If italics give you trouble, pick Alone Roman — the same palette with the italic channel removed and two hexes adjusted so nothing that italics used to separate collapses. If you want to keep Soft or Focused and only drop a few italics, VS Code's per-theme overrides still work:

"editor.tokenColorCustomizations": {
  "[Alone Soft]": {
    "textMateRules": [
      { "scope": ["comment", "string"], "settings": { "fontStyle": "" } }
    ]
  }
},
"editor.semanticTokenColorCustomizations": {
  "[Alone Soft]": {
    "enabled": true,
    "rules": {
      "interface": { "italic": false },
      "typeParameter": { "italic": false },
      "*.defaultLibrary": { "italic": false }
    }
  }
}

FAQ

Why no blue or cyan?

Two real reasons and one that used to be claimed. Real: blue text on a dark background defocuses relative to the rest of the line (chromatic aberration) and blooms for astigmatic eyes, and short-wavelength light drives melanopsin harder per unit brightness. Claimed: "blue bleaches rhodopsin and destroys dark adaptation" — true of the light, but reading is cone vision on a screen that already resets dark adaptation; see What it does not do.

Does it protect my night vision?

No. It stimulates rods less than a white-on-black theme at the same brightness (the golds about half as much, the neutrals about 85 % as much), and it is dimmer overall, but that is a comfort gain, not preserved dark adaptation. Red-only variants for that use case are on the roadmap.

Why italic for strings and comments?

Font style provides differentiation without requiring additional colours. Italics signal "different voice" — comments are authorial notes, strings are literal data. This lets us maintain distinguishability within a constrained warm palette. If italics don't work for you, use Alone Roman.

Why bold for keywords?

Keywords are control flow — the skeletal structure of your program. Bold weight provides immediate visual anchoring without requiring a brighter or more saturated colour.

Is this good for astigmatism?

Usually. Low text luminance and no blue are the two things that matter most for halation and fringing; the Roman variant removes italics as well. If you still see fringing, try Alone Soft, and drop the display brightness before pushing the theme brighter.

Can I use this in a lit room?

Alone is tuned for dark environments. In a bright room you may want higher contrast; the Standard variant is usually still comfortable in low ambient light.

Is it colour-blind safe?

For red-green deficiency, yes, and it is enforced: every meaning-carrying colour pair is checked under simulated protanopia and deuteranopia in all four variants (ΔE2000 ≥ 5 or a font-style difference), and the eight normal terminal slots stay ≥ ΔE2000 10 apart. Tritanopia is not simulated or enforced — a warm palette has little blue-yellow content for a tritanope to lose, but that also means some pairs (Types vs Functions, for example) sit closer under tritan simulation than the red-green threshold, and the bright ANSI slots are not checked against each other at all. If you have tritanopia, treat the theme as untested rather than verified.

Contributing

The shipped themes/*.json files are generated from themes/_src/; don't edit them directly. Build, verify, test and variant-authoring instructions are in CONTRIBUTING.md. Every numeric table in this README that sits between  markers is rendered by the verifier — change the palette, run node scripts/verify-palette.mjs --write-readme, and commit the result.

Issues

Found a bug or have feedback? Open an issue at github.com/crypticpy/alone/issues

License

MIT License. See LICENSE for details.

Acknowledgments

CIE 1951 scotopic luminosity function and the CIE S 026 melanopic action spectrum
APCA (Myndex) for the lightness-contrast model; Viénot, Brettel & Mollon (1999) for the CVD simulation matrices
The late-night coding community who inspired this work

Code alone. Code in peace. Your eyes will thank you.

Name		Name	Last commit message	Last commit date
.github		.github
docs		docs
images		images
samples		samples
scripts		scripts
terminal		terminal
tests		tests
themes		themes
.gitignore		.gitignore
.vscodeignore		.vscodeignore
CHANGELOG.md		CHANGELOG.md
CONTRIBUTING.md		CONTRIBUTING.md
LICENSE		LICENSE
README.md		README.md
package-lock.json		package-lock.json
package.json		package.json

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Alone

Variants

The Science

What "warm-only" means on a screen

The rod curve, for reference

Where the benefit actually comes from

What it does not do

Lightness spacing (L*)

Installation

VS Code Marketplace

From VSIX

From Source

Recommended Settings

Display Recommendations

OLED

Mini LED

Both

Color Palette

Syntax Colors

Bracket Pair Colors

Background Hierarchy

Theme Variants

Alone (Standard)

Alone Soft

Alone Focused

Alone Roman

Terminal Themes

Extension Compatibility

GitLens

Error Lens

Indent Rainbow

Todo Tree

Language Support

Accessibility

Contrast (WCAG and APCA)

Colour-vision deficiency

Astigmatism

Italics

FAQ

Why no blue or cyan?

Does it protect my night vision?

Why italic for strings and comments?

Why bold for keywords?

Is this good for astigmatism?

Can I use this in a lit room?

Is it colour-blind safe?

Contributing

Issues

License

Acknowledgments

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