The design 雪花

Tatami's Tokyo Night, made into a system.

A tour of Sekka's brand: the crest and where it comes from, Tatami's colours with their contrast measured, the type, the shapes and spaces the desktop already uses, and what isn't finished. This page is built from the same token file as the brand.

The crest

雪華, sekka, is an Edo-period word for snow crystals. In 1832 Doi Toshitsura published eighty-six of them, drawn through a microscope, as Sekka Zusetsu, and the patterns became a fashion in Edo design.

The mark is a yukiwa 雪輪, the snow ring of Japanese family crests: six circles of radius 76, centred 36 from the middle of a 256 grid, joined into a softly scalloped ring. A six-armed crystal is cut through it: arms from radius 19 to 84, one pair of branches on each, and a hollow hexagon at the centre. Arms point straight up.

It is drawn to stay clearly apart from NixOS's lambda snowflake. Sekka runs on NixOS; the two marks are never locked up together.

Six circles of radius 76 (dashed), centred 36 from the middle (dots), make the ring. The crystal is cut through it.

Lockups and sizes

The wordmark is JetBrains Mono ExtraBold, Tatami's own face, outlined so it never depends on installed fonts. Beside it, 雪花 stands vertically like a seal. On this page they take their colours from the theme.

Below 24px the crest loses its branches: the symbolic glyph thickens the cuts so they survive the pixel grid. The app icon sits on a square tile, because every Tatami surface is square.

SVG: lockup, Night · lockup, Day · crest · symbolic · app icon

Colour

Night is Tatami's own palette, value for value, from its bar, launcher, notifications, terminal and Displays window. Blue is the one accent: the focused window's border, today in the calendar, links and focus. Status colours always come with a word or an icon.

Day exists for documents and light pages; Tatami itself is dark only. High contrast is a third theme for people who need more: every text colour reaches 7:1 on every surface, and edges reach 3:1. The one colour that fails in Night is kept on purpose: Tatami's week numbers are 2.8:1, so that grey is only ever decoration.

Every colour in every theme. Ratios are computed when the site is built, against the darkest or lightest of the surfaces each colour sits on.
Token	Night	Day	High contrast
`surface`Ground of every Tatami surface: windows, bar, launcher, notifications, OSD and lock screen. Every text token is checked against it. High contrast deepens it so text reaches AAA.	`#1a1b26`ground	`#e1e2e7`ground	`#0b0c12`ground
`surface-raised`Cards, popovers and thumbnails in Displays. Day lightens instead of darkening, so text keeps its contrast. In High contrast a raised surface is barely lighter, so it always carries a border-inactive edge.	`#24283b`ground	`#eef0f5`ground	`#161925`ground
`selection`Selected text in the terminal and selected rows. text-strong, text and text-secondary stay at 4.5:1 or more on it in Night and Day, and 8:1 or more in High contrast.	`#292e42`ground	`#cdd1e2`ground	`#26304f`ground
`indigo`Dyed cloth: the noren in the Genkan icon and other large fields. text-strong reads 4.1:1 on it at night and 6.2:1 in High contrast, so only marks and text 24px or larger go on indigo.	`#3d59a1`text-strong 4.1:1 · large text only	`#3d59a1`text-strong 2.6:1 · decorative only	`#3d59a1`text-strong 6.2:1 · AA, short of AAA
`border-inactive`Unfocused window borders (Hyprland inactive_border). Decorative in Night and Day, under 3:1, so never the only edge of a control there. In High contrast it reaches 3.6:1 on every surface and edges raised surfaces and controls.	`#595959aa`1.5:1 · decorative	`#a1a6c5`1.6:1 · decorative	`#7a85b5`3.6:1 · meets 3:1
`text-faint`Week numbers and weekday labels in the bar's calendar. Kept exact from Tatami but only 2.8:1 (Night) and 2.5:1 (Day) on surface: decorative, repeated labels only, never meaning. High contrast lifts it to 7.3:1 or more.	`#565f89`2.2:1 · decorative only	`#848cb5`2.2:1 · decorative only	`#b7c0ea`7.3:1 · AAA
`text-secondary`Notification body text and other secondary copy, on surface, surface-raised and selection: 4.6:1 or more in Night and Day, 8.1:1 or more in High contrast.	`#939aba`4.8:1 · AA	`#47578f`4.6:1 · AA	`#c3cbee`8.1:1 · AAA
`text`Default foreground in the bar, terminal, launcher and windows, on surface, surface-raised and selection (6.4:1 Night, 4.5:1 Day, 10.2:1 High contrast at the lowest).	`#a9b1d6`6.4:1 · AA	`#3156ab`4.5:1 · AA	`#dde3fb`10.2:1 · AAA
`text-strong`Headings, the calendar's month, Displays' text and the wordmark's ink. 8.3:1 or more on every surface in Night and Day, 12:1 or more in High contrast.	`#c0caf5`8.3:1 · AAA	`#1a1b26`11.2:1 · AAA	`#f4f6ff`12.0:1 · AAA
`accent`The one accent: the focused window's 2px border, today in the calendar, notification and launcher borders, accent fills, links and focus rings. Text-safe on every surface (5.3:1 Night, 4.5:1 Day, 7.4:1 High contrast at the lowest).	`#7aa2f7`5.3:1 · AA	`#1357b5`4.5:1 · AA	`#a9c4ff`7.4:1 · AAA
`on-accent`Text and glyphs on accent fills, such as today's date: 6.8:1 Night, 6.9:1 Day, 11.2:1 High contrast.	`#1a1b26`6.8:1 on accent · AA	`#ffffff`6.9:1 on accent · AA	`#0b0c12`11.2:1 on accent · AAA
`crest`The crest's ink: always the accent, so the mark holds 4.5:1 or more on surface, surface-raised, selection and white in Night and Day, and 7.4:1 or more in High contrast.	`#7aa2f7`5.3:1 · meets 3:1	`#1357b5`4.5:1 · meets 3:1	`#a9c4ff`7.4:1 · meets 3:1
`danger`Screen recording, a Keep Awake request without a verified inhibitor, destructive actions and errors. Always with a word or icon. 7.6:1 or more on every High contrast surface.	`#f7768e`5.1:1 · AA	`#b3083a`4.6:1 · AA	`#ffb1c0`7.6:1 · AAA
`success`Applied and verified states. Always with a word or icon: never told from danger by hue alone. 9.9:1 or more on every High contrast surface.	`#9ece6a`7.3:1 · AAA	`#49602f`4.6:1 · AA	`#c2ef8e`9.9:1 · AAA
`warning`Pending and caution states. Always with a word or icon. 8.8:1 or more on every High contrast surface.	`#e0af68`6.7:1 · AA	`#705631`4.5:1 · AA	`#f8cf8c`8.8:1 · AAA
`purple`Terminal magenta and btop graphs. Data only, not interface chrome. 8:1 or more on every High contrast surface.	`#ad8ee6`5.0:1 · AA	`#7317ec`4.5:1 · AA	`#d5c2ff`8.0:1 · AAA
`teal`Terminal cyan and btop graphs. Data only, not interface chrome. 8.4:1 or more on every High contrast surface.	`#449dab`4.3:1 · large text only	`#0c6554`4.6:1 · AA	`#8fdde9`8.5:1 · AAA

Type

JetBrains Mono is the desktop's voice: the bar, the menu, the terminal and the wordmark. Kanji are set in Noto Serif JP, the brush-like mincho beside the mono's straight lines; on this site they are drawn as outlines, so nobody downloads a font for a handful of characters.

Long reading, like this, is set in Atkinson Hyperlegible Next, which the Braille Institute designed for low-vision readers. Inside the desktop, notifications use Liberation Sans. Every font here is served by this site.

wordmark 76px/1 · Brand

sekka

display 40px/44px · Brand

Welcome to Sekka

seal 42px/1 · Kanji

雪花

kanji-label 15px/22px · Kanji

玄関 · 畳 · 雪見

bar 12px/26px · Interface

Monday 10:23

bar-glyph 13px/26px · Interface

bar-glyph

terminal 12px/16px · Interface

sekka-update --status

notification 14px · Notifications

Restart to finish updating

h1 32px/40px · Prose

Why you shouldn't use Sekka (yet)

h2 22px/30px · Prose

Tatami: a desktop under your fingertips

body 16px/26px · Prose

Choose your disk, account, desktop, applications, and location.

caption 13px/20px · Prose

Current interface in preview mode, with sample data.

Shape and space

Corners are square everywhere; the crest is the one round thing. Borders are 2px: blue for the focused window, notifications and the launcher, a muted grey for windows in the background. Windows are 5px apart and 10px from the edge of the screen. Nothing casts a shadow.

This site is laid out the same way. Each block is a window; the one in blue has focus. The home page's sections sit like the mats of a four-and-a-half-mat room, where no four corners ever meet.

gap-in spacing: 5px Between tiled windows (Hyprland gaps_in).
bar-edge spacing: 8px Waybar's left and right margins.
notify-gap spacing: 8px Between stacked notifications.
gap-out spacing: 10px Between tiled windows and the screen edge (Hyprland gaps_out).
card-pad-y spacing: 10px Top and bottom padding inside a notification.
card-pad-x spacing: 12px Left and right padding inside a notification.
dialog-pad spacing: 18px Padding inside the launcher's menus.
radius-none radius: 0 Every Tatami surface: windows (Hyprland rounding 0), notifications, launcher, OSD and app tiles. The crest is the only round form.
bar-height size: 26px Waybar's height.
workspace-slot size: 20px Width of each workspace button in the bar.
indicator-slot size: 21px Width of the recording, night-light, silence and Keep Awake indicators.
icon-slot size: 27px Width of each tray and status icon slot.
card-width size: 380px Notification width.
border-width border: 2px Window, notification, launcher and focus borders.

The family

Genkan's icon is a noren, the split curtain that hangs in a Japanese entrance, dyed indigo with the crest across its slits as real cloth would have it. Tatami's is a four-and-a-half-mat room that also reads as tiled windows. Both are proposals; neither ships yet.

Yukimi's icon is the one it ships today: a round window onto a snowy night. It still uses NixOS blues and a cream frame, so it doesn't belong to this family yet.

Genkan, proposed

Tatami, proposed

Yukimi, as shipped

What isn't finished

The desktop doesn't use the crest yet. Tatami's bar shows the NixOS logo and Genkan's welcome page shows the NixOS snowflake.
Genkan and Yukimi are still light libadwaita with NixOS blues, not Tokyo Night, and Yukimi's icon is outside the family.
Tatami is dark only. Day and High contrast exist in the tokens and on this site, not in the desktop.
The week-number grey fails contrast in Night and Day, kept because it is Tatami's real value and only decorative.
Pages share no raster image, so links posted elsewhere show no picture.