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Functional Zǐsè

#643f63
Notes

Functional Zǐsè (#643F63) is a deep violet with an earthy character. It leans grounded and natural, the kind of color that plays well with wood, clay, linen, and warm neutrals. Its HSL profile (302°, 23%, 32%) places it in the muted band at a dark lightness. It works well as a headline, icon, or deep background in an otherwise light layout, pairing cleanly with cream, bone, and warm neutrals. For a confident two-color system, pair it with its complementary green. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#643f63
RGB
rgb(100, 63, 99)
HSL
hsl(302, 23%, 32%)
HWB
hwb(302 25% 61%)
OKLCH
oklch(42.4% 0.074 327.7)
P3
color(display-p3 0.3713 0.2535 0.3802)
HSV
hsv(302, 37%, 39%)
LAB
lab(32.18% 22.60 -14.64)
LCH
lch(32.18% 26.93 327.07)
CMYK
cmyk(0%, 37%, 1%, 61%)

Etymology

Functional
adjective

Latin fūnctiō, performance — adjectival suffix -al. As a color modifier, functional implies a clear-and-purpose-fit-and-utilitarian quality, the crisp color of Mid-Century-Modern and Bauhaus form-follows-function design-aesthetic. Sits at the crisp-and-functional end of the grid, parallel to practical and utilitarian in usage.

Zǐsè
noun

Chinese 紫色, deep purple color — the formal color name for imperial purple in Chinese color terminology, distinguished from the broader (purple). Zǐsè color refers to a Qing-dynasty qipao dress in formal court-purple silk: a saturated, slightly cool deep violet with the silk luster of multi-bath fermentation-and-mineral dye on tussah silk. Slightly warmer than Japanese murasaki.

Closest matches

The nearest named color in three reference sources, ranked by perceptual distance (ΔE76 in CIELAB). ΔE < 1 is imperceptible to most viewers; ΔE > 10 is clearly different. When two sources point to the same hex they’re merged into one tile; click any to open that color’s page.

Variations

Click any swatch to explore

Harmonies

Accessibility

Color-vision simulation

How this color appears to viewers with the four major color-vision-deficiency types. Computed via the Machado (2009) physiologically-based model. If a tile matches the original, the color reads the same to that viewer.

#643f63
Original
#3d4964
Protanopia
#464d62
Deuteranopia
#66424c
Tritanopia
#494949
Achromatopsia
WCAG contrast

The color used as foreground text against pure white and pure black, with the contrast ratio and WCAG 2.1 grade. Aim for AA (4.5:1) for body text and AA Large (3:1) for 18 pt+ headlines; AAA (7:1) is the gold standard for long-form reading surfaces.

The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAAon White
8.63:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
Failon Black
2.43:1

Wide gamut

Display P3 representation

The CSS Color 4 wide-gamut form of this color. Both swatches render the same color on every display — the P3 form only diverges from sRGB when a designer pushes channels outside sRGB's reach.

sRGB hex
sRGB hex
##643F63
Display P3
Display P3
color(display-p3 0.3713 0.2535 0.3802)
Inside sRGBOKLCH chroma 0.074

This color sits well within the sRGB cube. P3 and sRGB share the gray axis and most desaturated tones, so a P3 display renders this identically to an sRGB display.

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