#21397A
Closest named color: Twilight Blue (#0A437A). oklch(36.5% 0.115 265.7), rgb(33, 57, 122).
Aa
White text reads best on this color (10.87:1).
About this color
#21397A is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.115 and its hue 266°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.030 away. White text reads best on it, at 10.87:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.115) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.93:1 |
| White text | 10.87:1 |
Values
| HEX | #21397A |
| RGB | rgb(33, 57, 122) |
| HSL | hsl(224, 57%, 30%) |
| OKLCH | oklch(36.5% 0.115 265.7) |
Contrast
WCAG 2 contrast ratios are the conformance target: AA needs 4.5:1 for body text and 3:1 for large text, AAA needs 7:1. APCA Lc values are supplementary guidance from the WCAG 3 drafts.
| Pair | WCAG 2 | Result | APCA | APCA guidance |
|---|---|---|---|---|
| White text on #21397A | 10.87:1 | AAA | Lc -98.8 | Preferred for body text |
| Black text on #21397A | 1.93:1 | Fails | Lc 9.1 | Not readable |
| #21397A text on white | 10.87:1 | AAA | Lc 94.9 | Preferred for body text |
| #21397A text on black | 1.93:1 | Fails | Lc -7.8 | Not readable |
Tints and shades
A 50–950 scale built in OKLCH: the hue is held, lightness follows a Tailwind v4-like curve, and every step is kept inside the sRGB gamut. This color sits at step 900.
-
Step 50
50
#F2F5FE
oklch(97% 0.012 271.3)
-
Step 100
100
#E2EAFB
oklch(93.6% 0.025 265.6)
-
Step 200
200
#CAD9FA
oklch(88.5% 0.048 266)
-
Step 300
300
#A6C0F9
oklch(80.9% 0.086 265.5)
-
Step 400
400
#779DF6
oklch(70.6% 0.138 265.5)
-
Step 500
500
#5682F3
oklch(63.2% 0.176 265.6)
-
Step 600
600
#3D68E1
oklch(55.6% 0.191 265.7)
-
Step 700
700
#3055C4
oklch(49% 0.179 265.9)
-
Step 800
800
#28479E
oklch(42.8% 0.146 265.7)
-
Step 900
900 (this color)
#21397A
oklch(36.5% 0.115 265.7)
-
Step 950
950
#15244A
oklch(27% 0.073 265.6)
#21397A with color blindness
Simulated with the Machado et al. (2009) model. ΔE is how far the color moves: below about 0.02 you would not notice a change.
| Vision | Seen as | Shift (ΔE) |
|---|---|---|
| Protanopia (no red cones) | #11417C | 0.024 |
| Deuteranopia (no green cones) | #003979 | 0.024 |
| Tritanopia (no blue cones) | #004853 | 0.093 |
| Achromatopsia (no color) | #3D3D3D | 0.115 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #21397A
#21397A
oklch(36.5% 0.115 265.7)
- #503B00
#503B00
oklch(36.6% 0.075 86)
Analogous
Neighbouring hues, 30° either side.
Split complementary
The two hues beside the complement (150° and 210°).
Triadic
Three hues spaced 120° apart.
Palettes with this color
Curated palettes that contain a color within ΔE 0.04 (OKLab) of #21397A, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.030
- Marine Blue #01386A ΔE 0.038
- Cobalt #1E488F ΔE 0.052
- Prussian Blue #1D3557 ΔE 0.061
- Marine #042E60 ΔE 0.063
- Dark Slate Blue #483D8B ΔE 0.066
- Light Navy #155084 ΔE 0.066
- Dark Grey Blue #29465B ΔE 0.074
Use #21397A in your product
Turn it into light and dark UI roles checked for contrast, then export to Tailwind v4, shadcn/ui, CSS or design tokens.