#3578A3
Closest named color: Flat Blue (#3C73A8). oklch(54.9% 0.095 239.9), rgb(53, 120, 163).
Aa
White text reads best on this color (4.80:1).
About this color
#3578A3 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 55%, its chroma 0.095 and its hue 240°. Its hue sits on the cool side of the wheel. The nearest named color is Flat Blue (#3C73A8), ΔE 0.019 away. White text reads best on it, at 4.80:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | moderately saturated (0.095) |
| Temperature | cool |
| Nearest name | Flat Blue (#3C73A8) |
| Black text | 4.36:1 |
| White text | 4.80:1 |
Values
| HEX | #3578A3 |
| RGB | rgb(53, 120, 163) |
| HSL | hsl(203, 51%, 42%) |
| OKLCH | oklch(54.9% 0.095 239.9) |
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 #3578A3 | 4.80:1 | AA | Lc -78.6 | Fine for body text |
| Black text on #3578A3 | 4.36:1 | AA large text | Lc 31.0 | Non-text elements, placeholder text |
| #3578A3 text on white | 4.80:1 | AA | Lc 73.1 | Content text, not long reading |
| #3578A3 text on black | 4.36:1 | AA large text | Lc -28.6 | Dividers and decoration only |
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 600.
-
Step 50
50
#F2F6F9
oklch(97.1% 0.006 239.8)
-
Step 100
100
#E3EBF1
oklch(93.6% 0.012 239.9)
-
Step 200
200
#CCDCE8
oklch(88.6% 0.024 240.1)
-
Step 300
300
#A8C5DA
oklch(80.9% 0.043 239.6)
-
Step 400
400
#79A7C7
oklch(70.7% 0.068 239.3)
-
Step 500
500
#5591B9
oklch(63.2% 0.087 239.3)
-
Step 600
600 (this color)
#3578A3
oklch(54.9% 0.095 239.9)
-
Step 700
700
#29678E
oklch(49.2% 0.089 239.8)
-
Step 800
800
#245473
oklch(42.7% 0.073 239.9)
-
Step 900
900
#22455D
oklch(37.6% 0.058 240.6)
-
Step 950
950
#152936
oklch(27% 0.036 238.5)
#3578A3 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) | #6478A5 | 0.050 |
| Deuteranopia (no green cones) | #556DA2 | 0.042 |
| Tritanopia (no blue cones) | #008387 | 0.067 |
| Achromatopsia (no color) | #727272 | 0.095 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3578A3
#3578A3
oklch(54.9% 0.095 239.9)
- #9A6333
#9A6333
oklch(55% 0.095 59.8)
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 #3578A3, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Flat Blue #3C73A8 ΔE 0.019
- Dull Blue #49759C ΔE 0.020
- Muted Blue #3B719F ΔE 0.020
- Cerulean #457B9D ΔE 0.021
- Nice Blue #107AB0 ΔE 0.025
- Stormy Blue #507B9C ΔE 0.030
- Ocean Blue #03719C ΔE 0.035
- Sea Blue #047495 ΔE 0.036
Use #3578A3 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.