01The mark
A single 50/60 Hz cycle on a strict 24-unit grid. It starts as a true sine (cubic-approximated quarter waves) and, at x 12 — the meridian, the instant of transfer — drops into a square half-cycle, the stepped output of an inverter. The hairline is the time axis the whole product is organised around.
- Grid
- 24 × 24 units. Cycle spans x 3–21 (18 u) on axis y 12; both halves are 9 u wide and 7 u tall.
- Sine half
- Two cubic quarter-waves: C4.5 8.335 6 5 7.5 5 S10.5 8.335 12 12 — the tangent at the axis matches a true sine (slope aπ/2w).
- Square half
- A hard vertical at x 12, flat at y 19, returning at x 21. Miter joins, butt caps — no rounding anywhere.
- Stroke
- 2.5 u wave, 0.75 u axis. Favicon redrawn on a 16 px grid: 2 px stroke, axis dropped, cycle enlarged to fill the tile.
- Not
- No ring, bolt, shield, socket or feeder diagram. The silhouette is an open line — it never encloses a shape.
02Mark, icon, favicon, monochrome
The standalone mark, the app icon (ultramarine field, white cycle, ice axis) and the 16 px favicon are separate drawings, not scalings of each other.
03Wordmark and lockups
The wordmark is Instrument Sans at weight 620, width 88, tracked −10/1000 and outlined to paths. Its cap height is centred on the mark's axis so the name sits on the same time line as the cycle.
04Real-size proofs in context
Rendered at true 16 px and 32 px — not enlarged. At 16 px the favicon keeps the sine/square contrast; the axis is intentionally dropped.
MainsKeeper — InvestigationMainsKeeper — DuplexRouter adminmainskeeper.local/investigate?from=13:41&to=15:02MainsKeeperRunbooksStatus32 px · app switcher / taskbar
MainsKeeperPinned tab16 px · notification row
MainsKeeper · BW Rack UPS on battery · 15:09
Mark on dark ground, 32 px05Palette
Ultramarine is the presence: the header field, the mark, the now-edge and every selection. Everything else is cool and quiet so amber and crimson carry meaning. Ratios are WCAG contrast against cool paper #F5F7FB unless noted.
- #2436D9UltramarineBrand field, mark, now-edge, selection7.5:1 on paper · white on it 8.1:1
- #0B1233InkText, history banner, markers17.1:1
- #F5F7FBCool paperGround—
- #A9DDF3IceAccents on dark and on ultramarine; history wash tintNot for text on light (1.4:1)
- #5B6784SlateSecondary text, normal lane lines, hatching5.3:1
- #B86E00AmberWarning fills and glyphs · text uses #8A5200Fill 3.7:1 · text #8A5200 6.0:1
- #C8203FCrimsonCritical: on battery now5.2:1
- #0F7A5CCool greenHealthy glyphs5.0:1
Dark ground set (checked separately)
- #0A0F2CDark groundTerminal and dark proofs—
- #E6EBF7Text on darkBody text15.7:1 on #0A0F2C
- #A9DDF3IceMark on dark, measured values12.8:1
- #9AA6FFUltramarine, liftedHeadings/links on dark (#2436D9 is only 2.3:1 here)8.3:1
- #F2A93BAmber on darkEstimates, delayed9.4:1
- #FF6B84Crimson on darkCritical6.9:1
- #5FD3A8Green on darkHealthy10.2:1
06Typography
What happened, and how certain are we?
Instrument Sans · display & body · OFL
34 / 600 / w88Now · 15:22
20 / 600Contact lost — cause unknown
16 / 400 bodyAt least 27 minutes on battery; endpoint unknown.
13 / 500 labelUtility power · as seen at UPS input
Variable width axis used at 86–96 % for a tighter, engineered voice; tabular figures everywhere.
Martian Mono · data, times, axes · OFL
14:30–14:52
15:21:48 · batch 16 of 64
±90 s · est. 18 min · rcvd 15:17
0123456789 · 1,248 / 1,630
2026-09-30 15:22:00 local
07Interface language — certainty drawn, not coloured
The same encodings run through dashboard lanes, the mobile spine and the CLI characters. Each has a shape and a label; colour is only a second channel.
- Measured, normal — solid line
- Measured, on battery — solid bar
- Delayed — hollow, with received time
- Estimate — dashed, labelled “est.”
- No records — hatched
- Uncertain time — ±90 s bracket
- Endpoint unknown — fade + open arrow
- Contact lost — cause unknown
08Rationale
Time is the organising idea
Operators ask “what happened, and when did we know?” The mark is a cycle on a time axis; the product is lanes on a shared axis. Logo and interface share a grammar but are judged separately.
Precise, not dramatic
No bolts or alarms. A clean waveform change is the whole story of a UPS transfer — the vertical edge at x 12 is the meridian that gives the concept its name.
Ultramarine means “you are here”
Brand, now-edge and selection share one blue, so wherever the operator is looking in time is marked in the brand colour. History is framed in ink with a one-click return.
Honest about certainty
Measured, estimated, delayed, missing and uncertain each get a distinct shape — carried from lanes to phone to terminal.
09Files
logomark.svglogomark-mono.svglogomark-dark.svgwordmark.svgwordmark-light.svglockup.svglockup-dark.svglockup-mono.svglockup-on-ultramarine.svgapp-icon.svgfavicon.svgfonts/OFL.txt
Identity for MainsKeeper — concept 5, “Meridian”. Fictional demonstration data appears on product surfaces only.