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Fortified Forum Sapphire

#373bad
Notes

Fortified Forum Sapphire (#373BAD) is a true blue 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 (238°, 52%, 45%) places it in the balanced band at a mid lightness. It works across type, buttons, and borders, saturated enough to feel deliberate but balanced enough to not fight the rest of the palette. For a confident two-color system, pair it with its complementary yellow. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#373bad
RGB
rgb(55, 59, 173)
HSL
hsl(238, 52%, 45%)
HWB
hwb(238 22% 32%)
OKLCH
oklch(42.6% 0.178 274.4)
P3
color(display-p3 0.2186 0.2309 0.6533)
HSV
hsv(238, 68%, 68%)
LAB
lab(31.71% 35.64 -61.35)
LCH
lch(31.71% 70.95 300.15)
CMYK
cmyk(68%, 66%, 0%, 32%)

Etymology

Fortified
adjective

Latin fortificāre, to make strong — past-participle of fortify. As a color modifier, fortified implies a saturated-and-strengthened-and-defensive quality, the deep-rich color of Vauban-style military-fortification stone-and-earth rampart-and-bastion architecture. Sits at the bold-and-fortified end of the grid, parallel to bastioned and armored.

Forum
modifier

Latin forum, open-space-of-Roman-city. As a color modifier, forum implies a Roman-and-civic-meeting-square quality, the visual register of Roman-Forum-and-Pompeii-Forum hand-built civic-meeting-square forum-and-basilica-and-rostrum Republican-and-Imperial-Roman architectural surfaces under Roman-Forum-and-Pompeii civic-meeting-square light. Sits at the modifier-and-architecture end of the grid, parallel to agora and stoa in usage.

Sapphire
noun

An iron-and-titanium-bearing corundum — the same mineral as ruby, hardness 9 on the Mohs scale, mined for two millennia from Sri Lanka, Burma, Madagascar, and the Cashmere mines of British India. The color refers to a fine Kashmir-cut sapphire: a saturated, slightly violet-shifted deep blue with the gem's signature internal velvet — a quality of light scattering in the stone that faceted glass cannot replicate. Cooler than cobalt, deeper than azure.

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.

#373bad
Original
#0050b1
Protanopia
#0045ab
Deuteranopia
#00596e
Tritanopia
#424242
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
8.78:1
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
2.39:1

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
##373BAD
Display P3
Display P3
color(display-p3 0.2186 0.2309 0.6533)
P3 has subtle headroomOKLCH chroma 0.178

Moderately saturated colors gain a small bump in P3 — the difference is usually visible side-by-side on wide-gamut hardware but won't change the character of the color.

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