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spectr.pm vs Substack

Two design systems side by side, measured from the live sites — colour, type, shape, depth, components, states and responsive behaviour.

spectr.pm: Spectr - AI Product Ops: Meetings to PRDs, Specs & Stories · Above the fold
spectr.pm
spectr.pm· read 2026-10-14
Substack: Substack · Above the fold
Substack
substack.com· read 2026-11-03

Worth knowing

  • Interaction states are missing on at least one side — that site's stylesheets were cross-origin and could not be read.

Ground and ink

Each side painted in its own measured canvas, ink, muted and primary roles.

spectr.pm

Heading on canvas

Body copy in the measured muted role.

Primary action
18.6:1 ink on canvas

Substack

Heading on canvas

Body copy in the measured muted role.

Primary action
18:1 ink on canvas

Palette

Named roles first, then every colour measured without one.

spectr.pm

  • canvas#0D0D0D
  • surface#171717
  • ink#FAFAFA
  • hairline#2E2E2E
  • primary#894DEF
  • on-primary#FAFAFA

10 more, no measured role

Substack

  • canvas#161718
  • surface#FFFFFF
  • ink#FFFFFF
  • muted#808080
  • hairline#000000
  • primary#FF6719
  • on-primary#222222

7 more, no measured role

Type scale

Set at the measured size, weight, tracking and leading. Brand typefaces are not loaded, so the metrics are real and the letterforms are not.

spectr.pm

hero-display

288px · 900 · shown smaller

display

280px · 900 · shown smaller

display

252px · 900 · shown smaller

display

200px · 900 · shown smaller

display

132px · 800 · shown smaller

display

99px · 600 · shown smaller

h2

92px · 800 · shown smaller

Substack

h1

55px · 400 · shown smaller

heading

38px · 400

h3

32px · 500

h3

32px · 400

h3

24px · 700

h4

24px · 500

h4

24px · 400

Corners

Drawn at the measured radii.

spectr.pm

0px

Substack

0px

8px

pill

12px

4px

Spacing

One shared scale across both sides, so the bars are directly comparable.

spectr.pm

4
8
12
16
24
28
32
40

Substack

4
8
12
16
20
24
28
32

Depth

Shadows cast on each side's own ground.

spectr.pm

sm

Substack

sm

md

lg

xl

Buttons

Rendered from the measured computed styles.

spectr.pm

primaryfilledprimary-smtext

Substack

primarysecondaryicontext

The measured values behind the panels above.

spectr.pmSubstack

At a glance

GroundDarkDark
Corners — these differSharpPill
Display size — these differ288px55px
Spacing base4px4px
Accent colours — these differ87
Type families — these differ28
Ink on canvas — these differ18.6:118.0:1
Components — these differ1112

Colour roles

primary — these differ#894DEF#FF6719
link—#B37767
canvas — these differ#0D0D0D#161718
surface — these differ#171717#FFFFFF
ink — these differ#FAFAFA#FFFFFF
body — these differ#B8B8B8#EEEEEE
muted—#808080
hairline — these differ#2E2E2E#000000
on-primary — these differ#FAFAFA#222222

Full palette

Every colour each extraction kept, including the ones with no measured role.

All colours — these differ#894DEF#A273F2#14532D#78350F#166534#4ADE80#92400E#FBBF24#0D0D0D#171717#FAFAFA#B8B8B8#2E2E2E#6B6B6B#000000#262626#FF6719#B37767#2A1A1E#342831#2F6D5D#3A261C#8AE1A2#774134#161718#FFFFFF#EEEEEE#808080#777777#222222#000000#363737
Semantic——

Typography

Families — these differInter-e4c28016845df4efJetBrains Mono-33799697913f1f09system-uiSF Pro DisplayCahuengaArialSF Compactmonospaceui-monospace-apple-system-ui-serif
hero-display288px · 900 · 288px · -11.52px · uppercase · Inter-e4c28016845df4ef—
display132px · 800 · 198px · -2.64px · Inter-e4c28016845df4ef—
h1 — these differ72px · 800 · 72px · -2.52px · Inter-e4c28016845df4ef55px · 400 · 68.2px · -0.23px · Cahuenga
h244px · 800 · 46.2px · -1.32px · Inter-e4c28016845df4ef—
h4—24px · 500 · 30px · 0px · Cahuenga
h3 — these differ19px · 600 · 28.5px · 0px · Inter-e4c28016845df4ef24px · 700 · 28px · 0px · SF Pro Display
heading — these differ16px · 600 · 24px · 0px · Inter-e4c28016845df4ef18.72px · 700 · 24px · -0.23px · system-ui
list-item — these differ16px · 500 · 24px · 0px · Inter-e4c28016845df4ef19px · 400 · normal · -0.23px · SF Pro Display
body — these differ15px · 500 · 23.25px · 0px · Inter-e4c28016845df4ef13px · 400 · 17px · 0px · system-ui
button — these differ15px · 600 · 22.5px · 0px · Inter-e4c28016845df4ef15px · 600 · 20px · 0px · system-ui
nav-link—15px · 400 · 20px · -0.23px · system-ui
input—15px · 400 · 20px · 0px · system-ui
quote—15px · 400 · 20px · 0px · system-ui
link — these differ14px · 500 · 20px · 0px · Inter-e4c28016845df4ef19px · 400 · normal · 0px · system-ui
code — these differ13px · 600 · 19.5px · 1.82px · uppercase · JetBrains Mono-33799697913f1f0915px · 400 · 20px · 0px · monospace
caption — these differ12px · 500 · 16.5px · 0px · Inter-e4c28016845df4ef11px · 500 · 20px · 0.2px · uppercase · SF Compact

Shape and rhythm

Radius — these differ0px0px4px8px12px9999px
Spacing — these differ4px8px12px16px24px28px32px40px44px48px64px144px4px8px12px16px20px24px28px32px40px48px80px120px
Border widths1px1px

Depth

Strategy — these differsingle-tierprogressive
Shadows — these differrgba(0, 0, 0, 0) 0px 0px 0px 0px, rgba(0, 0, 0, 0) 0px 0px 0px 0px, rgba(0, 0, 0, 0.1) 0px 10px 15px -3px, rgba(0, 0, 0, 0.1) 0px 4px 6px -4pxrgba(255, 255, 255, 0.2) 0px 1px 0px 0px inset, rgba(0, 0, 0, 0.1) 0px -1px 0px 0px insetrgba(0, 0, 0, 0.1) 0px 10px 15px -3px, rgba(0, 0, 0, 0.05) 0px 4px 6px -2pxrgba(0, 0, 0, 0.05) 0px 1px 2px 0pxrgba(0, 0, 0, 0.2) 0px 0px 12px 0px
Gradients — these differ—section: linear-gradient(rgba(41, 44, 70, 0.75), rgba(41, 44, 70, 0.75)), nonesection: linear-gradient(rgba(87, 78, 50, 0.75), rgba(87, 78, 50, 0.75)), nonesection: linear-gradient(to right, rgb(22, 23, 24) 16px, oklch(0.203939 0.00252193 248.11 / 0))section: linear-gradient(rgba(0, 0, 0, 0) 0%, rgba(0, 0, 0, 0) 50%, rgb(0, 0, 0) 100%)section: linear-gradient(rgba(76, 74, 73, 0.75), rgba(76, 74, 73, 0.75)), nonesection: linear-gradient(rgba(72, 72, 72, 0.75), rgba(72, 72, 72, 0.75)), nonesection: linear-gradient(oklch(0.243142 0.027467 333.61 / 0) 0%, oklch(0.243142 0.027467 333.61) 25%)section: linear-gradient(rgba(77, 77, 77, 0.75), rgba(77, 77, 77, 0.75)), nonesection: linear-gradient(oklch(0.240843 0.0254423 4.81479 / 0) 0%, oklch(0.240843 0.0254423 4.81479) 25%)section: linear-gradient(rgb(47, 109, 93), rgb(47, 109, 93)), nonesection: linear-gradient(oklch(0.203939 0.00252193 248.11 / 0) 0%, oklch(0.203939 0.00252193 248.11) 25%)
Opacity — these differ1.000.700.900.940.650.360.600.950.92
Z-index — these differdropdown 10dropdown 50base 1base 2dropdown 10dropdown 11

Components

Sharedbutton-primarybutton-textcardnavigationlinkbutton-primarybutton-textcardnavigationlink
Only here — these differbutton-filledbutton-primary-smbutton-text-2card-lgfooterlink-smbutton-secondarybutton-iconbutton-text-smnavigation-smlink-2card-featuredcard-sm
Signature——

Interaction states

Read from each site's own stylesheets. An empty side means they were cross-origin and unreadable.

Measured — these differother:focus-visibleinput:hoverother:hovercard:hoverother:focusother:disablednav:hovernav:focus-visible—

Responsive

Breakpoints — these differ375→343px · 6col768→704px · 3col1024→960px · 5col1280→1216px · 5col1440→1376px · 5col375→225px768→768px1024→1024px1280→1280px1440→1440px

Themes

Measured on the live site, not derived.

SupportSingle themeSingle theme

How this was measured

Differences here are ours, not the brands'.

Pages read66
Extracted — these differ2026-10-142026-11-03
Stylesheets — these differReadablePartly blocked
Roles unassigned — these differ107

Measured by DesignMD from the live sites. Compare two others. Generate a DESIGN.md for your own site.