Pairs DESIGN.md

Design System Inspiration of Pairs (ペアーズ)

Overview

Visual Theme & Atmosphere

Pairs is a Japanese dating app run by 株式会社エウレカ (Eureka, Inc.) in Tokyo. In May 2015 Match Group, the US online-dating company, acquired Eureka outright and kept Pairs running as its own brand. The stylesheet looks beyond Japan: alongside the Japanese font stack it carries one for Korean and one for Traditional Chinese.

The landing page is light, soft and teal. A brand cyan #00c1d4 carries every interactive border and label, a pale #e0f8fc tints whole sections, text sits in a green-grey #325151 rather than black, and the calls to action sit on a mint-to-cyan gradient — #70dfab to #3bd6cb to #20cfe3. Everything round is fully round.

What makes it worth reading:

• The gradient is an image token. --color-pairs-gradient is not a CSS gradient but a url(data:image/png…) — a 29×6 PNG stretched across the button. Its colours had to be read off its pixels.
• Every type step has two sizes. --text-headline-0-pc is 2.5rem and --text-headline-0-sp 1.875rem — the desktop and smartphone sizes are separate tokens, not a fluid scale.
• Hover inverts. The gradient buttons turn white with a teal label; the outline button fills.

Primary tasks

• Sign up (新規登録); start free; log in.
• Read member stories and the "happiness report".

Brand Narrative

Pairs sells trust in a category that needs it, and the page looks it: clean, soft and pale, with a single fresh teal and no hard edges. The gradient — mint into cyan — is the one flourish, and it is spent on the button that starts everything.

The token set reads like a product built for more than one country and more than one screen: a font stack per market, a type scale that names its desktop and phone sizes separately, and a brand ramp kept apart from a generic blue so that the two never blur. A Tailwind build sits underneath, but the brand decisions are written as Pairs' own tokens on top of it.

Principles

• One teal, one gradient. Teal for interaction, the gradient for the first step.
• Soft, not black. Green-grey text on white and pale teal.
• Two screens, two sizes. Every type step names both.

Personas

Not researched. No persona claim is made from a UI capture.

Colors

Measured with getComputedStyle on www.pairs.lv: 217 root custom properties, 264 across all rules. Tailwind v4's are excluded — --tw-*, the stock --text-xs…6xl, --radius-sm…3xl, --font-weight-*, tracking and leading defaults, and Tailwind's own lab() greys (--color-gray-100…900), none of which paints anything on the page. About 100 remain, Pairs' own.

Teal — the brand

--color-pairs-blue-00…06 (there is no -04):

• Primary (#00c1d4) — pairs-blue-03. The most-painted teal: the login button's border and label, every hover label and border (9 backgrounds, the interactive colour).
• Primary Link (#0096a9) — pairs-blue-01, also --color-fontColor-link.
• Primary Strong (#00aec2) — pairs-blue-02, accent text (17 elements).
• Primary Deep (#007f90) — pairs-blue-00.
• Primary Light (#a5eaf5) — pairs-blue-05, the login button's hover fill.
• Primary Surface (#e0f8fc) — pairs-blue-06, section backgrounds (10).

A separate, bluer ramp, --color-blue-00…04 (#007bcc first), is not the brand teal. Keep them apart.

The gradient

--color-pairs-gradient is url(data:image/png;base64,…), a 29×6 raster. Sampled across its middle row at x = 0, 7, 14, 21 and 28 it reads #70dfab, #3bd6cb, #20cfe3, #40d2e5, #46d2e5 — Gradient Start (#70dfab), a mint; Gradient Mid (#3bd6cb), a teal; Gradient End (#20cfe3), a cyan, easing slightly lighter at the right edge. It is the background of both sign-up buttons.

Ink and neutrals

--color-gray-00…07: #0a2c2f · #325151 · #678181 · #96aaaa · #bfcfcf · #dae4e5 · #ebf2f2 · #f4fbfb — greys with a green-teal cast throughout.

• Ink (#0a2c2f) — gray-00, --color-fontColor-primary. --color-fontColor-secondary is the same at 70%.
• Foreground (#325151) — gray-01. The colour of most <p> text on the page.
• Gray 02 (#678181) · Gray 03 (#96aaaa).
• Border (#dae4e5) — gray-05. The hairline on 934 elements — the page separates things with lines, not shadows.
• Gray 06 (#ebf2f2) · Surface (#f4fbfb) — gray-07 · Canvas (#ffffff).

--color-fontColor-placeholder is #22252766 — a different near-black at 40%, rendered on placeholder text.

Status and accents

Red #d03138 (ramp to #ef3f45 and #ffefeb) · Green #028541 · Yellow #f1bf00 · Orange #ff8831 · Purple #6e7de2 · Blue #007bcc.

Typography

Font family

--font-sans-ja is "Roboto", "Noto Sans JP", system-ui, sans-serif, and body, headings and buttons all compute it. document.fonts shows Roboto 400 and 700 and Noto Sans JP 400 and 700 loaded — Roboto for Latin letters and numerals, Noto Sans JP for Japanese. Both are open Google-published faces, recorded as what is served.

The same stylesheet carries --font-sans-ko ("Nanum Gothic"), --font-sans-ko-noto-sans-kr and --font-sans-zh-tw ("Noto Sans TC") for Korean and Traditional Chinese; they are not used on the Japanese page.

Scale — two sizes per step

Headlines are always 700 and body and captions always 400 — weight marks the family, size marks the step. --breakpoint-pc is 1024px.

Layout

• Lines, not shadows: the #dae4e5 hairline separates cards, lists and sections.
• Pale teal bands (#e0f8fc) alternate with white to structure the long page.
• Desktop and smartphone are designed as two sizes of one scale, switched at --breakpoint-pc.

Responsive Behavior

Not measured beyond the tokens: desktop 1440×1000 only. The -sp sizes and --breakpoint-pc: 1024px describe the phone layout; it was not rendered.

Elevation & Depth

One shadow on the page: rgba(0,0,0,0.2) 0 0 18px 0, a soft centred glow, used once. Elevation is otherwise absent.

Motion & Easing

The buttons transition over 0.3s. No motion token is published.

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Tier 1 sources: https://www.pairs.lv/ (live landing page — 217 root custom properties read via getComputedStyle, Tailwind v4 excluded; the --color-pairs-gradient PNG decoded and sampled by pixel; four components measured at rest, hover, pressed and focus; Roboto and Noto Sans JP loaded, captured 2026-09-26); https://www.pairs.lv/zz-this-does-not-exist (nonsense-path control — a real HTTP 404, 「ページが見つかりませんでした。」, captured 2026-09-26); https://eure.jp/ (株式会社エウレカ corporate site, read 2026-09-26)

Regional sources: https://thebridge.jp/en/2015/05/eureka-acquired-by-match-group (BRIDGE, 2015-05 — "Japan's Eureka, developer of dating and couple apps, acquired by Match Group"); https://www.globaldatinginsights.com/news/02062015-japanese-dating-developer-eureka-acquired-by-the-match-group/ (Global Dating Insights — "Japanese Dating Developer Eureka Acquired By The Match Group")

Components

Four components, every state on its own page load, focus read before the mouse moved.

• Sign up (header) — the brand gradient with a white 16px/700 label, a pill 36px tall. Hover and press drop the gradient: the button turns white with a #00c1d4 label and a 2px #00c1d4 border, over 0.3s.
• Start free (large) — the same gradient and the same inversion, 72px tall, 18px/700, 90px radius.
• Log in — transparent with a 2px #00c1d4 border and label. Hover fills #a5eaf5 and turns the label white.
• Testimonial cards — links with #000000 text and a #dae4e5 hairline. Nothing changes on hover or press.

The two button patterns are mirror images: the filled gradient empties to an outline, the outline fills.

Focus is the browser's

Every measured control shows Chrome's auto ring under :focus-visible. No focus colour is recorded. The header navigation (ホーム, 料金) could not be isolated on the page and is not measured.

Radius

Pills everywhere for buttons (a 9999px-class radius, 12 elements); cards at 24px (18) and 16px (14); 90px on the large button; a few one-offs (48px, 40px).

States

Four components. Hover: the gradient buttons invert to white with a teal label and border; the login button fills pale teal with a white label; testimonial cards do not change. Focus is the browser's auto ring throughout. No disabled state was observed.

Do's and Don'ts

Do

• Use #00c1d4 for interactive borders and labels, and the mint-to-cyan gradient for the primary call to action.
• Set text in the green-grey #325151 (or #0a2c2f for emphasis), not black.
• Separate with #dae4e5 hairlines.
• Pick the -pc or -sp size of a type step rather than scaling one size.

Don't

• Don't use the --color-blue-* ramp as the brand colour; the brand is --color-pairs-blue-*.
• Don't count Tailwind's lab() greys or stock text sizes as Pairs tokens.
• Don't recreate the gradient as brighter or more saturated than its sampled stops.

Voice & Tone

Not assessed as authored voice.

Agent Prompt Guide

Quick Color Reference

#00c1d4 brand teal · gradient #70dfab → #3bd6cb → #20cfe3 · #0096a9 link · #a5eaf5 light · #e0f8fc surface · #325151 text · #0a2c2f ink · #dae4e5 hairline · #f4fbfb / #ffffff backgrounds · #d03138 red

Example Component Prompts

• "A 36px pill: linear-gradient(90deg, #70dfab, #3bd6cb, #20cfe3), white 16px/700; hover turns it white with a #00c1d4 label and 2px #00c1d4 border."
• "An outline pill: 2px #00c1d4 border and label; hover fills #a5eaf5 with a white label."

Governance

Known Gaps

• Contrast, card-testimonial. Text #000000 on #00000000 measures 1.00:1, below the WCAG AA 4.5:1 minimum for normal-size text. Recorded as measured, not adjusted.