#273C5ANautilus (#273C5A) is a dark, muted blue with an OKLCH hue of 257°, lightness 0.35 and chroma 0.059. It sits on the cool side of the color wheel. In practice it behaves as a mid-weight working color for secondary surfaces and editorial blocks.
| HEX | #273C5A |
|---|---|
| RGB | rgb(39, 60, 90) |
| HSL | hsl(215, 40%, 25%) |
| HSV | hsv(215, 57%, 35%) |
| CMYK | cmyk(57%, 33%, 0%, 65%) |
| CIE Lab | lab(25 1.6 -20.5) |
| OKLCH | oklch(0.353 0.059 257) |
Under warm 2700K interior light Nautilus shifts subtly: leans toward purple; in north-facing or shaded light it is virtually unchanged. Overall drift across common illuminants is small (max ΔE ≈ 1.2), so it is a lighting-stable choice.
#2c3b54 — ΔE 1.2, shifts subtly: leans toward purple#2a3d58 — ΔE 0.7, is virtually unchanged#273c5a — ΔE 0.0, is virtually unchanged#273c5b — ΔE 0.2, is virtually unchangedTest Nautilus in the color lighting simulator — sweep it through daylight, warm 2700K light, 4000K LED, and shade alongside the rest of your palette.
Against white it measures 11.17:1 and against black 1.88:1, so white text is the stronger pairing. That pairing passes WCAG AA for body text. Avoid black text on this color entirely.
One color explored: close hues with real lightness and chroma structure, so the palette is the anchor through value rather than a set of colors.
#97a8bf · #6f829c · #4a5e7b · #273c5a · #0a1d36 · #000315
The anchor's neighbours on the wheel — everything shares an undertone, so the chord carries color without anything having to be muted to get along.
#346375 · #26506c · #273c5a · #21284e · #1e1739 · #160724
The mid-gap pairing — sage and mustard, terracotta and olive. A foil rotated 40–65° toward warm or cool: too far to be kin, too near to argue, carried by temperature and a deliberate value offset.
#b7a8c3 · #7992b5 · #806694 · #5c5166 · #273c5a · #0c2240
One deliberately opposed voice — a single restrained counterpoint across the wheel, or temperature against temperature where the anchor is too muted to carry a loud opposite.
#dfbd8c · #6b7a8f · #515a66 · #273c5a · #132033 · #030812
The anchor as the only color in the room. True neutrals or complement-warmed near-neutrals let it stay dominant.
#f6f1ea · #b4bac4 · #88847f · #4d545e · #273c5a · #28241e
This color as a ground rather than a subject — its own restraint held across a narrow value band, carrying one saturated voice from the opposite temperature.
#eaf3ff · #bfcbdb · #929fb2 · #273c5a · #000519 · #f5b64e
The opposite hue on the perceptual wheel, tempered to field strength — warm/cool tension without vibration.
#d1dfbb · #d2bd75 · #9381a6 · #6d5145 · #273c5a · #051319
The complement's two neighbours instead of the complement itself — strong contrast with a lower clash risk.
#fbf0e1 · #dbaf99 · #898852 · #714834 · #273c5a · #27260f
Three hues spaced evenly around the wheel; the anchor leads and the other two are held at supporting strength.
#ffeded · #deabac · #6f9063 · #425c38 · #273c5a · #351d1e
Two complementary pairs offset by 90° — the richest chord, kept usable by a strict lightness hierarchy.
#feecf5 · #d8abc1 · #9e7f50 · #2c5f4c · #273c5a · #2f220f
#455874 · #64758F · #8494AA · #A6B4C6 · #CAD4E3
#1F324D · #182941 · #112035 · #0A172A · #050F1F
#2C3C54 · #303C4D · #343C47
Its moderate chroma lets it work in mid-size areas — upholstery, secondary UI surfaces, editorial blocks — without overwhelming neighbors. In palettes it pairs most predictably with its tonal ramp and analogous neighbors; reserve the complementary hue for small, deliberate contrast.