---
version: alpha
name: Usefathom
description: Light design system extracted from usefathom.com (DOM-true values, Emblematic extractor 0.2.0, 2026-11-12).
colors:
  background: "#FFFFFF"
  surface: "#F4F6F5"
  on-surface-variant: "#4E5551"
  on-surface: "#242925"
  primary: "#6A51EC"
  gray-9: "#353B37"
  gray-2: "#ECEEED"
  color-8: "#000000"
  color-9: "#333740"
  on-primary: "#FFFFFF"
  background-dark: "#1D201E"
  on-surface-dark: "#FFFFFF"
  on-surface-variant-dark: "#DCE0DD"
  surface-dark: "#333835"
  primary-dark: "#A28FFF"
typography:
  display-lg:
    fontFamily: SF Pro (system-ui)
    fontSize: 56px
    fontWeight: 700
    lineHeight: 0.95
    letterSpacing: -0.025em
  headline-md:
    fontFamily: SF Pro (system-ui)
    fontSize: 40px
    fontWeight: 700
    lineHeight: 0.95
    letterSpacing: -0.015em
  title-md:
    fontFamily: SF Pro (system-ui)
    fontSize: 18px
    fontWeight: 600
    lineHeight: 1.5
  body-md:
    fontFamily: SF Pro (system-ui)
    fontSize: 18px
    fontWeight: 400
    lineHeight: 1.6
  body-sm:
    fontFamily: Jb
    fontSize: 13.6px
    fontWeight: 400
    lineHeight: 1.5
  label-md:
    fontFamily: SF Pro (system-ui)
    fontSize: 14.4px
    fontWeight: 400
    lineHeight: 1.4
rounded:
  xs: 6px
  sm: 10px
  md: 12px
  lg: 14px
  full: 9999px
spacing:
  xxs: 2.5px
  xs: 3px
  sm: 4px
  md: 5.5px
  lg: 7px
  xl: 8px
  2xl: 9.5px
  3xl: 10px
  4xl: 11px
  5xl: 12px
  6xl: 13px
  7xl: 16px
  8xl: 19px
  9xl: 24px
  container: 880px
components:
  button-primary:
    backgroundColor: "{colors.primary}"
    textColor: "{colors.background}"
    rounded: "{rounded.full}"
    padding: 10.8px
    height: 31.2px
    typography: "{typography.label-md}"
---

# Usefathom

> Extracted from [https://usefathom.com/](https://usefathom.com/) on 2026-11-12 by Emblematic. Every value below was read from the rendered DOM (computed styles, `document.fonts`, and the fonts Chrome actually used to paint text), not estimated from pixels. When the YAML front matter and this prose disagree, the YAML wins. Copy values from this file exactly; don't transcribe them from memory. Don't copy logos, imagery, illustrations or marketing copy.

## Overview

Usefathom uses a light canvas (#FFFFFF) with a palette led by #6A51EC. Type is set in **SF Pro (system-ui)** (display + body), **Jb** (mono), with 18px body text. Layout: 880px container, none-detected navigation, 10 sections. Built with astro, vercel.

## Colors

Area-weighted from painted backgrounds, text and borders on the 1440px light capture. Roles are inferred from usage (largest background, most text, interactive fills). Every hex is an exact computed value; a role marked *unverified* is a best guess that has not passed review, so its canonical token (e.g. `primary`) is left out of the front matter.

| Token | Hex | OKLCH | Role | Share of paint | CSS variable |
|---|---|---|---|---|---|
| `background` | `#FFFFFF` | 1 0 0 | bg | 76.0% | `--gray-0` |
| `surface` | `#F4F6F5` | 0.971 0.002 165.1 | surface | 9.1% | `--gray-1` |
| `on-surface-variant` | `#4E5551` | 0.442 0.011 161 | muted | 8.3% | `--gray-8` |
| `on-surface` | `#242925` | 0.274 0.01 151.4 | text | 2.8% | `--gray-11` |
| `primary` | `#6A51EC` | 0.553 0.222 283.8 | accent | 0.69% | `--purple` |
| `gray-9` | `#353B37` | 0.345 0.011 156.6 | other | 2.0% | `--gray-9` |
| `gray-2` | `#ECEEED` | 0.947 0.003 165.1 | other | 0.59% | `--gray-2` |
| `color-8` | `#000000` | 0 0 0 | other | 0.25% | — |
| `color-9` | `#333740` | 0.337 0.017 266.4 | other | 0.20% | — |

Contrast: text on background 14.8:1, muted text 7.66:1, accent 5.25:1.

The site responds to `prefers-color-scheme: dark`; the `-dark` tokens hold the dark-mode roles.

## Typography

| Family | Role | Weights | Share of text | Source |
|---|---|---|---|---|
| **SF Pro (system-ui)** (CSS: `-apple-system`) | display, body | 400, 500, 600, 700 | 89.3% | system (stack `-apple-system, "system-ui", sw, Helvetica, Arial, sans-serif`, resolved on macos) |
| **Jb** (CSS: `jb`) | mono | 400 | 10.7% | webfont |

Declared in `@font-face` but not used to paint text on this page: Font Awesome 6 Pro, Sw, Sw i. Don't treat these as the page's fonts.

Scale (px): 13.5, 14.5, 15, 17, 18, 23, 24, 40, 56. Effective ratio ≈ 1.328 (close to a perfect fourth). Body 18px at line-height 1.5; display 56px with tracking -0.025em. Headings are sentence case. On a 390px viewport the body is 16px and display 36px.

## Layout

Spacing has no reliable single base unit; the most used steps are 2.5, 3, 4, 5.5, 7, 8, 9.5, 10, 11, 12, 13, 16, 19, 24px. Sections open with about 72px of space before their first line of text. Content sits in a 880px container on a 12-column grid. Text density 0.146 (text area / page area).

Section order (desktop). Kinds below the review threshold are shown as *section*:

1. **nav** (43px, bg #FFFFFF)
2. **hero** — “Analytics without the cookies” (2174px, bg #FFFFFF)
3. **section** — “We sell software, not data” (1006px, bg #FFFFFF)
4. **section** — “A lightweight script for a fast website” (532px, bg #FFFFFF)
5. **logos** — “Trusted by 1,000,000+ websites and counting” (1744px, bg #FFFFFF)
6. **section** — “Getting started with Fathom is easy” (407px, bg #FFFFFF)
7. **logos** — “Fathom easily with all content management systems and developer frameworks” (810px, bg #FFFFFF)
8. **faq** — “Frequently asked questions” (643px, bg #FFFFFF)
9. **section** — “Website analytics deserved better, so we built something better” (377px, bg #FFFFFF)
10. **footer** — “Fathom Analytics” (519px, bg #F4F6F5)

## Elevation & Depth

Style: elevated. Most used shadows:

- `rgba(31, 33, 38, 0.12) 0px 14px 40px 0px`
- `rgba(23, 28, 25, 0.04) 0px 1px 2px 0px, rgba(56, 46, 107, 0.18) 0px 14px 36px -10px`

## Shapes

Dominant corner radius 6px; radii in use: 6px, 10px, 12px, 14px, pill. Borders: hairline (1px).

## Components

- **button-primary**: backgroundColor `#6A51EC`, textColor `#FFFFFF`, rounded `9999px`, padding `10.8px 12px`, height `31.2px`, fontFamily `SF Pro (system-ui)`, fontSize `13.6px`, fontWeight `500` (e.g. “Start free trial”)

## Do's and Don'ts

- Do reserve `#6A51EC` for primary actions and highlights; it covers only 0.69% of the painted page.
- Do set body copy in SF Pro (system-ui) at 18px / 1.5.
- Do tighten large headlines (-0.025em at 56px).
- Don't introduce font weights beyond 400, 500, 600, 700.
- Do keep corners at 6px for most controls, and use the larger radii only for cards and media.
- Don't copy this site's logos, illustrations, photography or copy; use the system, not the brand assets.

## Provenance

Spec v2, extractor 0.2.0. Render quality: **ok**. Vision pass: not run. Fields below confidence 0.7 are hedged or left out above: `color.accent_strategy`, `layout.columns`, `layout.hero`, `layout.section_count`, `space.base`, `space.section_padding_px`. Full per-field provenance is in `spec.json`.