# Stack Overflow design system

> Stack Overflow design system measured from stackoverflow.com: #1B75D0 primary on #FFFFFF, 12 color hex codes, type scale, spacing and a free DESIGN.md.

Canonical page: https://sitepeel.dev/design-md/stackoverflow.com/

Stack Overflow’s website (stackoverflow.com) uses the visitor’s system fonts and #1B75D0 as its main color on a white background. Measured by Sitepeel on November 4, 2026.

## What font does Stack Overflow use?

Stack Overflow uses the visitor’s system fonts on stackoverflow.com: no web font was measured. Measured on November 4, 2026.

- system-ui (weights 400, 700)

## Stack Overflow colors: palette and hex codes

Stack Overflow’s main colors are #FFFFFF (white) for the background, #0C0D0E (charcoal) for text and #1B75D0 (blue) as the main accent, with #E7700D (vivid orange) as another accent. Measured on November 4, 2026.

- #FFFFFF: white
- #0C0D0E: charcoal
- #3B4045: cool graphite
- #636B74: cool slate
- #EDF5FD: cool snow
- #F1F2F3: mist
- #E3E6E8: mist
- #BABFC5: cool silver

## What is Stack Overflow built with?

Stack Overflow’s website (stackoverflow.com) is built with jQuery, Svelte and Cloudflare. Measured on November 4, 2026.

- JavaScript framework: jQuery 3.7.1, Svelte 5
- Hosting & CDN: Cloudflare
- Marketing & support: OneTrust 202604.2.0
- Analytics: Google Analytics

## Questions and answers

### What font does Stack Overflow use?

No web font was measured on stackoverflow.com: it uses the visitor’s system fonts.

### What are the Stack Overflow colors and hex codes?

On stackoverflow.com: #FFFFFF (white) for the background, #0C0D0E (charcoal) for text and #1B75D0 (blue) as the main accent, with #E7700D (vivid orange) as another accent. The color palette above lists all 12 colors with their hex codes and where each one is used.

### What is the Stack Overflow design system?

The design system on this page is stackoverflow.com’s, as measured on November 4, 2026: #1B75D0 as the main color and 4px corners, written down as a DESIGN.md. It is not Stack Overflow’s own documentation.

### What is Stack Overflow built with?

Stack Overflow’s website (stackoverflow.com) is built with jQuery, Svelte and Cloudflare. The full tech stack Sitepeel found: jQuery, Svelte, Cloudflare, OneTrust and Google Analytics. Measured on November 4, 2026.

### What is the Stack Overflow DESIGN.md?

A plain-text file with Stack Overflow’s measured colors, type, spacing, corners and components as tokens, plus short rules, in the DESIGN.md format Google published with Stitch. Your AI coding agent reads it and builds in this style. More about DESIGN.md.

### How do I use it with Claude Code or Cursor?

Download the file and put it in your project’s root folder, then ask your agent to follow DESIGN.md. Step-by-step guides: Claude Code, Cursor, Codex, GitHub Copilot.

### Is this Stack Overflow’s official design system?

No. Sitepeel measured it from stackoverflow.com’s public page on November 4, 2026. It is an independent analysis, not made or approved by Stack Overflow.

### Can I use Stack Overflow’s style in my own product?

Use it to learn, prototype and compare. For a real product, make the style your own, and never copy Stack Overflow’s logo, name, pictures or text.

### How accurate are the values?

Each value was measured on the rendered page after it fully loaded, on desktop and mobile: colors where they appear, type with tracking, spacing, corners, shadows and hover states. Sites change, so check the date at the top.

## Files

- [DESIGN.md](https://sitepeel.dev/design-md/stackoverflow.com/DESIGN.md): the plain file to put in your project.
- [All brand DESIGN.md files](https://sitepeel.dev/design-md/examples/index.md)

Independent analysis by Sitepeel (sitepeel.dev), not affiliated with Stack Overflow.

## The DESIGN.md file

```markdown
---
version: alpha
name: Stack Overflow
description: "Light interface measured from stackoverflow.com: system-ui type, blue accents, tonal surfaces and 4px corners."
colors:
  background: "#FFFFFF"
  surface: "#FFFFFF"
  on-surface: "#0C0D0E"
  on-background: "#0C0D0E"
  on-surface-variant: "#3B4045"
  on-surface-muted: "#636B74"
  surface-container-low: "#EDF5FD"
  surface-container: "#F1F2F3"
  surface-container-high: "#E3E6E8"
  outline: "#F1F2F3"
  outline-variant: "#BABFC5"
  primary: "#1B75D0"
  on-primary: "#FFFFFF"
  secondary: "#E7700D"
typography:
  headline-display:
    fontFamily: system-ui
    fontSize: 15px
    fontWeight: 400
    lineHeight: 1.3
  body-md:
    fontFamily: system-ui
    fontSize: 17px
    fontWeight: 400
    lineHeight: 1.31
  body-lg:
    fontFamily: system-ui
    fontSize: 19px
    fontWeight: 400
    lineHeight: 1.31
  body-sm:
    fontFamily: system-ui
    fontSize: 13px
    fontWeight: 400
    lineHeight: 1.31
  caption:
    fontFamily: system-ui
    fontSize: 11px
    fontWeight: 400
    lineHeight: 1.31
  label-lg:
    fontFamily: system-ui
    fontSize: 15px
    fontWeight: 700
    lineHeight: 1.3
  label-md:
    fontFamily: system-ui
    fontSize: 13px
    fontWeight: 700
    lineHeight: 1.31
  label-sm:
    fontFamily: system-ui
    fontSize: 12px
    fontWeight: 700
    lineHeight: 1.85
rounded:
  sm: 4px
  md: 6px
  full: 9999px
spacing:
  xs: 4px
  sm: 8px
  md: 12px
  lg: 24px
  xl: 56px
components:
  button-primary:
    backgroundColor: "{colors.primary}"
    textColor: "{colors.on-primary}"
    typography: "{typography.body-sm}"
    rounded: "{rounded.md}"
    padding: 8px 10.4px
    height: 33px
  button-primary-hover:
    backgroundColor: "#155CA2"
  button-outline:
    backgroundColor: "{colors.surface-container}"
    textColor: "{colors.on-surface-variant}"
    typography: "{typography.label-sm}"
    rounded: "{rounded.sm}"
    padding: 0px 4px
    height: 24px
  button-outline-hover:
    backgroundColor: "{colors.surface-container-high}"
    textColor: "{colors.on-surface}"
  button-ghost:
    backgroundColor: "{colors.surface-container}"
    textColor: "{colors.on-surface}"
    typography: "{typography.label-md}"
    rounded: "{rounded.md}"
    padding: 8px
    height: 33px
  input-field:
    backgroundColor: "{colors.background}"
    textColor: "{colors.on-surface-variant}"
    typography: "{typography.body-sm}"
    rounded: "{rounded.md}"
    padding: 7.8px 9.1px 7.8px 32px
  card:
    backgroundColor: "{colors.background}"
    textColor: "{colors.primary}"
    typography: "{typography.body-sm}"
    rounded: "{rounded.sm}"
    padding: 0px
  link:
    textColor: "{colors.on-surface-variant}"
---

# Stack Overflow Design System

## Overview

The interface is light, built on **White (#FFFFFF)** with **Charcoal (#0C0D0E)** text, and **Blue (#1B75D0)** as the main accent.

Type is set in **system-ui**. Headlines run large; body text is 17px. The surface language is flat. Corners are mostly 4px.

Measured from [stackoverflow.com](https://stackoverflow.com/questions) on November 4, 2026 at 1440×900 and 390×844 from 377 rendered elements. Values are computed styles from the live page, not the original source files.

## Colors

The palette has 12 roles.

- **White (#FFFFFF):** Page background, seen 17 times. Token `background`.
- **Charcoal (#0C0D0E):** Primary text and headings, seen 21 times. Token `on-surface`.
- **Cool Graphite (#3B4045):** Secondary text, seen 59 times. Token `on-surface-variant`.
- **Cool Slate (#636B74):** Muted text and metadata, seen 44 times. Token `on-surface-muted`.
- **Cool Snow (#EDF5FD):** Raised areas one step from the page, seen 1 time. Token `surface-container-low`.
- **Mist (#F1F2F3):** Cards and panels, seen 32 times. Token `surface-container`.
- **Mist (#E3E6E8):** Hover and pressed fills, seen 1 time. Token `surface-container-high`.
- **Mist (#F1F2F3):** Borders and dividers, seen 31 times. Token `outline`.
- **Cool Silver (#BABFC5):** Secondary dividers, seen 1 time. Token `outline-variant`.
- **Blue (#1B75D0):** Primary buttons and calls to action, seen 19 times. Token `primary`.
- **White (#FFFFFF):** Text and icons on primary. Token `on-primary`.
- **Vivid Orange (#E7700D):** Accent, seen 1 time. Token `secondary`.

## Typography

**system-ui** carries the whole interface. Fallback stack: `-apple-system, BlinkMacSystemFont, Segoe UI Adjusted, Segoe UI`.

- **headline-display:** system-ui 15px at weight 400, line height 1.3. Page title (h1).
- **body-md:** system-ui 17px at weight 400, line height 1.31. Body text.
- **body-lg:** system-ui 19px at weight 400, line height 1.31. Lead paragraphs.
- **body-sm:** system-ui 13px at weight 400, line height 1.31. Secondary and small text.
- **caption:** system-ui 11px at weight 400, line height 1.31. Captions and fine print.
- **label-lg:** system-ui 15px at weight 700, line height 1.3. Large buttons and tabs.
- **label-md:** system-ui 13px at weight 700, line height 1.31. Buttons, navigation and labels.
- **label-sm:** system-ui 12px at weight 700, line height 1.85. Small labels and badges.

## Layout

Spacing does not follow a strict grid: 52% of measured values are multiples of 4px, so match the measured steps rather than rounding to a grid.

- **Scale:** xs 4px, sm 8px, md 12px, lg 24px, xl 56px.
- **Breakpoints:** 607px, 640px, 640.1px, 771px, 816px, 816.1px, 947px, 980px, 980.1px, 1100px, 1111px, 1264px.

## Elevation & Depth

The design is flat: no shadows were measured. Hierarchy comes from tonal surface steps (#EDF5FD → #F1F2F3 → #E3E6E8) and #F1F2F3 borders.

## Shapes

Most elements use 4px corners. Measured radii, most used first:

- **sm (4px):** 212 elements.
- **md (6px):** 26 elements.
- **full (9999px):** 12 elements.

## Components

Measured from the rendered page. Token values reference the tokens above.

- **button-primary (“Sign up”):** #1B75D0 fill, #FFFFFF text, 13px/400, 6px radius, padding 8px 10.4px.
- **button-primary-hover:** background #155CA2, text #FFFFFF on hover.
- **button-outline (“python”):** #F1F2F3 fill, #3B4045 text, 12px/700, 4px radius, padding 0px 4px, border 1px solid #F1F2F3.
- **button-outline-hover:** background #E3E6E8, text #0C0D0E on hover.
- **button-ghost (“Questions”):** #F1F2F3 fill, #0C0D0E text, 13px/700, 6px 0px 0px 6px radius, padding 8px.
- **input-field (“Search…”):** #FFFFFF fill, #3B4045 text, 13px/400, 6px radius, padding 7.8px 9.1px 7.8px 32px, border 1px solid #BABFC5.
- **card:** #FFFFFF fill, #1B75D0 text, 13px/400, 4px radius, padding 0px.
- **link:** transparent fill, #3B4045 text, padding 0px.

## Do's and Don'ts

- Do use #FFFFFF for the page and lift surfaces in small steps: #EDF5FD, #F1F2F3, #E3E6E8.
- Do keep text in 3 levels: #0C0D0E, #3B4045, #636B74.
- Do reserve #1B75D0 for primary actions and key highlights.
- Do reuse the measured spacing steps (8px, 12px, 24px).
- Do use 4px corners on most elements; larger surfaces also use 6px.
- Don't add drop shadows for depth; use tonal surfaces.
- Don't introduce new font families beyond system-ui.
- Don't use #1B75D0 for large backgrounds or body text.
- Don't make interface transitions slower than 0.2s.

## Motion

Interface transitions are quick: 0.2s.

- **Easing:** `cubic-bezier(0.165, 0.84, 0.44, 1)`.
- **Reduced motion:** the page responds to `prefers-reduced-motion`.

Generated by [Sitepeel](https://sitepeel.dev/design-md/stackoverflow.com/), the free DESIGN.md generator (engine 2026.10.29+b828a475ee10).

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