LangChain — decoded design system

langchain.com · dark · modern · custom · deep decode — measured live

LangChain's design system, decoded live by Mozaika: measured color roles, type scale, buttons with real hover/focus states, motion and the brand's own tokens.

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This is a static, crawlable rendering for search & AI engines. The interactive version — filters, live decode console, copy & export — is at https://mozaika.design/decode/langchain.com.

Decoded design system

LangChain's decoded design system: background #030710, text #CCE9FF, accent #7FC8FF, link #030710, primary #CCE9FF; type scale h1 56px / h2 32px / body 16px; 4px spacing base; 18px base radius. The single interactive/action color is #E5F4FF — used only on interactive or must-notice elements (buttons, links, key highlights), never on large fills.

Color roles

Using these colors

• Action color #E5F4FF — the single interactive color; only on things you click or must notice, never large fills.
• secondary, button_bg are all #E5F4FF — one role, not several (the action color).
• accent #7FC8FF — accent for emphasis — keep it rare on the page.
• primary #CCE9FF — ≈ the text color — a foreground/text color, not an action color (action = #E5F4FF).
• link #030710 — fails contrast on the background (~1.0:1) — this is a dark UI color, NOT a readable link; use the text or action color for links (verify against the reference).

Typography

• Heading: Twklausanne
• Body: Aeonik
• h1: 56px
• h2: 32px
• body: 16px

Spacing

• base unit: 4px
• scale: 8px, 10px, 12px, 16px, 18px, 20px, 22px, 24px, 32px, 43px

Radii

• base: 18px
• button: 6px

Shadows (elevation)

• overlay: rgba(127, 200, 255, 0.5) 0px 0px 32px 0px

Motion

Micro-interactions run at 300ms (dominant) with ease.

• durations: 300ms · 200ms · 500ms
• easings: ease · ease-out
• animated properties: opacity

Native design tokens

…and 44 more measured on the page.

Button states (measured)

• primary hover: box-shadow rgba(127, 200, 255, 0.4) 0px 0px 20px 4px
• primary focus: outline 1px auto rgb(16, 16, 16)

Layout (measured)

• container max-width: 1416px
• nav: 72px sticky

Motion choreography (measured)

Load order: a.swiper-slide×10 → h1.t-heading-1-rg → a.banner-link → a.banner-link → div.embed-icon×9 → a.navbar2_logo-link

Responsive (measured)

• breakpoints: 479px · 767px · 992px
• mobile (390px): hero 36px · nav hamburger

Install it

Drop this measured system into any shadcn/Tailwind project in one command:

npx shadcn add mozaika.design/r/decode/langchain.com

registry item · or query it over MCP: get_design_system("LangChain")

Export: DESIGN.md

# LangChain — Design System

> dark, modern, medium, custom — deep decode (measured live)

## Colors

| Role | Value |
|------|-------|
| bg | `#030710` |
| surface | `#0F141E` |
| border | `#212833` |
| text | `#CCE9FF` |
| text_muted | `#7F93A4` |
| primary | `#CCE9FF` |
| accent | `#7FC8FF` |
| link | `#030710` |
| secondary | `#E5F4FF` |
| button_bg | `#E5F4FF` |
| button_text | `#030710` |

**Using these colors**

- **Action color** `#E5F4FF` — the single interactive color; it appears only on things you click or must notice (buttons, key highlights), never on large fills or backgrounds.
- `secondary`, `button_bg` are all `#E5F4FF` — one role, not several (your action color).
- **accent** `#7FC8FF` — accent for emphasis — keep it rare on the page.
- **primary** `#CCE9FF` — ≈ the text color — a foreground/text color, not an action color (action = #E5F4FF).
- **link** `#030710` — fails contrast on the background (~1.0:1) — this is a dark UI color, NOT a readable link; use the text or action color for links (verify against the reference).
- **Page coverage** (full-page screenshot pixels): `#030710` 85.1% · `#398BDC` 7% · `#0C1521` 5.3% · `#234465` 2.6%

## Typography

- Heading: **Twklausanne** _(free fallback: Newsreader)_
- Body: **Aeonik** _(free fallback: Space Grotesk)_

| Role | Size / weight · line-height · tracking |
|------|------------------------------------------|
| hero | 56px / 300 · lh 62px · tracking -1.68px |
| h2 | 32px / 300 · lh 35px · tracking -0.96px |
| body | 16px / 300 · lh 22px |
| small | 14px / 400 · lh 14px |

- Weight ladder: 300 · 400 — use these exact measured weights, not the 400/600 defaults.

> **Fonts —** Twklausanne may be proprietary — safe free fallback: Newsreader (Google Fonts). Aeonik is proprietary — closest free match: Space Grotesk (Google). Load Space Grotesk; keep Aeonik first so licensed users still get it.

## Spacing
- base unit: 4px (inferred from the measured scale)
- measured scale: 8px, 10px, 12px, 16px, 18px, 20px, 22px, 24px, 32px, 43px — snap all gaps/padding to these

## Radius
- base: 18px
- button: 6px
- card: 6px

## Buttons

| Button | Fill / text | Border | Radius | Padding | Font | Shadow |
|--------|-------------|--------|--------|---------|------|--------|
| primary | `#E5F4FF` / `#030710` | none | 6px | 12px 18px 12px 18px | 400 14px | none |
| secondary | `rgba(0, 0, 0, 0)` / `#CCE9FF` | 1px solid rgb(47, 75, 104) | 6px | 12px 18px 12px 18px | 400 14px | none |

**States (measured, not guessed)**

- primary hover: box-shadow `rgba(127, 200, 255, 0.4) 0px 0px 20px 4px`
- primary focus: outline `1px auto rgb(16, 16, 16)`
- secondary hover: box-shadow `rgba(127, 200, 255, 0.3) 0px 0px 20px 2px`
- transition: `all 0.3s ease`

## Shadows (elevation)
- overlay: `rgba(127, 200, 255, 0.5) 0px 0px 32px 0px`

## Motion
- durations: 300ms (dominant) · 200ms · 500ms
- easings: `ease` (dominant) · `ease-out`
- animated properties: opacity

Micro-interactions use the dominant duration + easing; nothing on the page animates slower than the longest duration above — don't invent springier motion.

## Their own tokens (verbatim from :root)

| Token | Value |
|-------|-------|
| `--colors--violet--violet-100` | `#f8f7ff` |
| `--colors--green--green-400` | `#1d3d3c` |
| `--dark--button-text` | `#1d3d3c` |
| `--colors--blue--blue-500` | `#043e5d` |
| `--colors--green--green-300` | `#8b9c9c` |
| `--colors--violet--violet-400` | `#beb4fd` |
| `--nav--button-text` | `#1d3d3c` |
| `--colors--violet--violet-300` | `#cfc8fe` |
| `--red--button-text` | `#772730` |
| `--colors--green--green-100` | `#e9ecec` |
| `--colors--red--red-400` | `#772730` |
| `--colors--blue--blue-400` | `#076597` |

_…and 42 more measured on the page._

Prefer these names when extending their system — it's the brand's actual vocabulary.

## Layout (measured)
- container max 1416px
- nav: 72px sticky

| Section (y) | Height | Cols | Gap | Pad y | Split |
|---|---|---|---|---|---|
| 126 | 434 | — | — | 0/0 | — |
| 560 | 1302 | — | — | 0/0 | — |

## Motion choreography (measured)
Load order: `a.swiper-slide`×10 @0ms → `h1.t-heading-1-rg` @0ms → `a.banner-link` @256ms → `a.banner-link` @256ms → `div.embed-icon`×9 @256ms → `a.navbar2_logo-link` @256ms

Rebuild the timeline, not just the durations — order, delays and staggers above are the choreography.

## Responsive (measured)
- breakpoints: 479px · 767px · 992px
- mobile (390px): hero 36px · body 16px · nav: hamburger

## How to apply
Paste the Tailwind `@theme` (or CSS variables) as your base, then build each
section to its spec — verify every color, radius, and font against these tokens.
Hover/focus states, shadows and motion timings above are measured from the live page — match them exactly, don't re-guess them.

← All decoded design systems

An automated reading of LangChain's publicly-visible CSS (colors, fonts, spacing, motion) — not affiliated with langchain.com. No screenshots stored. Removal requests: hello@mozaika.design.