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blue · cool

#3f3f52

a dark, muted blue · cool · closest name: Dark Slate Blue

Token name suggestion: Forest Sapphire

RGB
63, 63, 82
HSL
240°, 13%, 28%
CMYK
23, 23, 0, 68
Luminance
0.0522

#3f3f52 is a dark muted blue, 240° on the wheel and 62/100 on the cool side. Put white text on it (10.27:1). As text it scores 10.27:1 on white — safe at any size. Nearest name is Dark Slate Blue, nearest Tailwind family is zinc.

hsl(240 13% 28%)rgb(63 63 82)Base step 800AAA inkCool

At a glance

Every number on this page in one read: what #3f3f52 is made of, how bright it looks, and which way it leans.

Hex
#3f3f52
Hue
240°
blue
Saturation
13%
muted
Lightness
28%
dark
Brightness
32%
HSV value
Perceived
26%
weighted brightness
Luminance
0.0522
WCAG relative
Temperature
Cool
62/100 cool
Color family
Blue
Tone
Muted
Best ink
White
10.27:1
Closest name
Dark Slate Blue
ΔE2000 14.9
Chroma
12.4
LCH, 0–130ish
OKLCH L
0.376
perceptual lightness
Tailwind
zinc
500 · ΔE 18.3
Web-safe
#333366
nearest of 216
Where it sits
Hue240° of 360°
Saturation13%
Lightness28%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #3f3f52.

Temperature
Warm ← → Cool62% cool

Reads cool. Warm and cool siblings keep the same lightness, so you can swap one in without redoing your contrast maths.

Luminance by channel
Red20%
Green68%
Blue12%

Green carries most of what the eye calls brightness — that is why WCAG weights it 0.7152.

Every format

HEX#3f3f52
HEX (8-digit)#3f3f52ff
RGBrgb(63, 63, 82)
RGBArgba(63, 63, 82, 1)
HSLhsl(240, 13%, 28%)
HSV / HSBhsv(240, 23%, 32%)
HWBhwb(240 25% 68%)
CMYKcmyk(23%, 23%, 0%, 68%)
LABlab(27.4 4.8 -11.4)
LCHlch(27.4 12.4 292.6)
OKLCHoklch(0.376 0.032 284.7)
XYZ (D65)xyz(5.35, 5.22, 8.71)
Decimal4144978
Display P3color(display-p3 0.247 0.247 0.322)
Web-safe#333366

Copy-ready code

every platformclick to select
/* CSS */
color: #3f3f52;
background-color: #3f3f52;
/* CSS custom property */
--brand: #3f3f52;
/* Tailwind (arbitrary) */
class="text-[#3f3f52] bg-[#3f3f52]"
/* SCSS */
$brand: #3f3f52;
/* SwiftUI */
Color(red: 0.247, green: 0.247, blue: 0.322)
/* UIKit */
UIColor(red: 0.247, green: 0.247, blue: 0.322, alpha: 1)
/* Android XML */
<color name="brand">#3F3F52</color>
/* Android Compose */
Color(0xFF3F3F52)
/* Flutter */
Color(0xFF3F3F52)
/* Python / OpenCV (BGR) */
(82, 63, 63)
/* Python / PIL (RGB) */
(63, 63, 82)
/* Java AWT */
new Color(63, 63, 82)
/* .NET */
Color.FromArgb(255, 63, 63, 82)
/* OpenGL / Unity (0–1) */
(0.2471f, 0.2471f, 0.3216f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{63,63,82}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #3f3f52 85%, white);
border-color: color-mix(in oklab, #3f3f52 40%, transparent);
/* theme-aware in one line */
color: light-dark(#373748, #DCDCE4);
/* relative colour syntax */
--hover: hsl(from #3f3f52 h s calc(l - 7));

Design tokens

The same ramp in the four formats a team actually needs. Paste one and the whole palette lands with it.

css custom propertiesclick to select
:root {
  --brand-50: #F7F7F8;
  --brand-100: #EEEEF1;
  --brand-200: #DADAE2;
  --brand-300: #C0C0CE;
  --brand-400: #A0A0B6;
  --brand-500: #80809D;
  --brand-600: #6A6A8A;
  --brand-700: #595973;
  --brand-800: #3f3f52;
  --brand-900: #363645;
  --brand-950: #22222B;
  --brand: #3f3f52;
  --brand-ink: #ffffff;
  --brand-surface: #F6F6F8;
  --brand-border: #D1D1DC;
  --brand-hover: #2F2F3E;
  --brand-pressed: #20202A;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #181820;
    --brand-ink: #DCDCE4;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F7F7F8',
        100: '#EEEEF1',
        200: '#DADAE2',
        300: '#C0C0CE',
        400: '#A0A0B6',
        500: '#80809D',
        600: '#6A6A8A',
        700: '#595973',
        800: '#3f3f52',
        900: '#363645',
        950: '#22222B',
        DEFAULT: '#3f3f52',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F7F7F8,
  '100': #EEEEF1,
  '200': #DADAE2,
  '300': #C0C0CE,
  '400': #A0A0B6,
  '500': #80809D,
  '600': #6A6A8A,
  '700': #595973,
  '800': #3f3f52,
  '900': #363645,
  '950': #22222B,
);
$brand-base: #3f3f52;
$brand-ink: #ffffff;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F7F7F8", "$type": "color" },
      "100": { "$value": "#EEEEF1", "$type": "color" },
      "200": { "$value": "#DADAE2", "$type": "color" },
      "300": { "$value": "#C0C0CE", "$type": "color" },
      "400": { "$value": "#A0A0B6", "$type": "color" },
      "500": { "$value": "#80809D", "$type": "color" },
      "600": { "$value": "#6A6A8A", "$type": "color" },
      "700": { "$value": "#595973", "$type": "color" },
      "800": { "$value": "#3f3f52", "$type": "color" },
      "900": { "$value": "#363645", "$type": "color" },
      "950": { "$value": "#22222B", "$type": "color" }
    },
    "brandInk": { "$value": "#ffffff", "$type": "color" }
  }
}

Best text color

Only one of black and white can be right. This is the one, with the number that proves it.

Readable at a glance#ffffff on #3f3f52 · 10.27:1
Use #ffffffAAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 10.27:1 · recommended
AA pass · AA large pass · AAA pass
Aa
Black text · 2.04:1
AA fail · AA large fail · AAA fail
Reading the other direction: #3f3f52 as text scores 10.27:1 on white and 2.04:1 on black.
Best tinted ink on it, if plain black or white feels flat: #F1F1F4 at 9.11:1.

Make it accessible

A contrast checker tells you that you failed. This tells you what to ship instead — same hue, same saturation, lightness moved only as far as WCAG demands.

The quick fox
#3f3f52 · 10.27:1
AA on whitealready passes
#3f3f52
The quick fox
#3f3f52 · 10.27:1
AAA on whitealready passes
#3f3f52
The quick fox
#737393 · 4.60:1
AA on black+23% L
#737393
The quick fox
#9393AC · 7.01:1
AAA on black+34% L
#9393AC

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #3F3F52 is enough for headings on white. Non-text elements such as icons, chart strokes and focus rings also sit at 3:1 under WCAG 2.2 (1.4.11).

Accessibility — WCAG contrast

Aa
#3f3f52 on white: 10.27:1
AA ✓ pass · AA-large · AAA
Aa
#3f3f52 on black: 2.04:1
AA ✗ fail · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #3f3f52 as text on that neutral, and that neutral as text on #3f3f52.

NeutralRatioBoth directions
White10.27:1AaAa
Slate 509.82:1AaAa
Slate 1009.38:1AaAa
Slate 2008.33:1AaAa
Slate 3006.92:1AaAa
Slate 4004.01:1AaAa
Slate 5002.16:1AaAa
Slate 6001.36:1AaAa
Slate 7001.01:1AaAa
Slate 8001.42:1AaAa
Slate 9001.74:1AaAa
Black2.04:1AaAa
Colour vision deficiency
true color
protanopia · #3A4153
deuteranopia · #3A4051
tritanopia · #3B4245

Roughly one man in twelve has some form of colour vision deficiency. If any of the three panels above is hard to tell apart from a neighbouring colour in your palette, add a shape, an icon or a label so the meaning does not rest on hue alone.

Color scale — 50 to 950

A Tailwind-shaped ramp built around this exact hex. #3f3f52 is pinned to step 800; the rest hold its hue and let saturation ease off at the extremes so the pale end never turns neon.

#F7F7F8
#EEEEF1
#DADAE2
#C0C0CE
#A0A0B6
#80809D
#6A6A8A
#595973
#3f3f52
#363645
#22222B
Base = 800Lightest = 50 · #F7F7F8Darkest = 950 · #22222BText step on white = 600
Perceptual ramp — OKLCH

The same eleven steps expressed in OKLCH, where equal lightness numbers actually look equally spaced. HSL ramps go muddy in the yellows and washed out in the blues; this one does not. Modern browsers render it natively — the hex ramp above is the fallback.

50100200300400500600700800900950
oklch tokensclick to select
:root {
  --brand-50: oklch(0.97 0.008 284.7);
  --brand-100: oklch(0.94 0.013 284.7);
  --brand-200: oklch(0.88 0.019 284.7);
  --brand-300: oklch(0.80 0.025 284.7);
  --brand-400: oklch(0.72 0.030 284.7);
  --brand-500: oklch(0.64 0.032 284.7);
  --brand-600: oklch(0.56 0.032 284.7);
  --brand-700: oklch(0.48 0.030 284.7);
  --brand-800: oklch(0.40 0.027 284.7);
  --brand-900: oklch(0.32 0.023 284.7);
  --brand-950: oklch(0.24 0.018 284.7);
}

Colors that work with #3f3f52

Not a palette — a role sheet. Each swatch answers one question you will hit while building the component.

Text on it#ffffff
White wins here
Surface#F6F6F8
Tinted page background
Border#D1D1DC
Hairlines and dividers
Muted text#646482
Captions on the surface
Accent#554F3C
Second voice, not a rival
Dark variant#373748
Hover, pressed, headers
Light variant#F1F1F4
Selected rows, tints
Dark surface#181820
Dark-mode background
Hover#2F2F3E
One step down in lightness
Pressed#20202A
Two steps down
Disabled#707091
Chroma pulled out
Focus ring#404066
Offset from the fill so it reads
Light mode
Everything in its place

Surface, border, heading and body all derive from this one hue, so the screen stays coherent without a second palette.

Primary actionSecondaryBadge
Dark mode
Same hue, inverted

Lightness flips, hue holds. The accent stays the anchor in both themes.

Primary actionSecondaryAccent

In real components

The same eight roles, wired into the interface patterns you will actually build with them. Every state below is a computed value, not a mock-up.

Buttons and states
Save changesHoverPressedDisabled
OutlineSubtleLinkFocused
Form field
you@company.com

Focus ring uses the light variant so the field still reads as one shape.

Send me product updates
Notice
Your export is ready

The file stays available for seven days. Download it before it expires.

NewBetaDraft
Data
Storage used68%
Acme LtdActive
NorthwindTrial
GlobexActive

How to use #3f3f52

Derived from its contrast, chroma and lightness — not from taste.

Works well for
  • Body text and links on white
  • Borders, dividers and quiet backgrounds
  • Long-form reading surfaces
  • Headers, footers and dark-mode surfaces
  • Brand accents, badges and data highlights
Use with care
  • Text on black or near-black surfaces
  • Black text placed on it
  • Pairing with a same-lightness hue — edges vibrate
Minimum size as text on white
Any size
Safe as a fill behind white type
Yes
Safe as a 1px border on white
Yes

Meaning and mood

What a colour in this family tends to signal, and how this particular chroma and lightness change the reading.

trustedcalmcompetentcorporate

The default of institutions for a reason: blue is read as stable and safe across nearly every culture that has been surveyed.

With almost no chroma left, the family association is barely present; treat it as a neutral that happens to lean this way. The low lightness adds weight and formality.

Worth knowing

It is also the most crowded hue on the web. Distinctiveness has to come from your other choices.

Reads as
  • FormalityHigh
  • EnergyLow
  • Weight72/100
  • TemperatureCool
  • ApproachabilityBalanced

Colour associations are cultural and vary by market. Treat these as a starting point for a conversation with your audience, not a finding about them.

Similar colors

One move away from this hex in each direction. Every swatch is its own page.

Color relationships

The wheel positions with their names attached, so you can grab the one you actually need.

Complementary#52523F
Analogous left#3F4852
Analogous right#483F52
Split-complement 1#52483F
Split-complement 2#48523F
Triadic 1#523F3F
Triadic 2#3F523F
Tetradic#523F48
On the wheel
Base+30°−30°+120°+240°+180°240°

#3f3f52 sits at 240°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red24.7%
Green24.7%
Blue32.2%
R · 0–255
63
0x3f
G · 0–255
63
0x3f
B · 0–255
82
0x52

CMYK percentages

Cyan23.2%
Magenta23.2%
Yellow0.0%
Key (black)67.8%

Total ink coverage is 114%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#3f3f52 text on a black background

contrast 2.04:1

Card sample

#3f3f52 text on a white background

contrast 10.27:1

Card sample

#3f3f52 on grey

9.38:1

#3f3f52 on its own surface

9.52:1

#3f3f52 on its dark surface

1.72:1

CSS3 live lab

Text font color

The quick brown fox

color: #3f3f52;
Background color
Panel with #3f3f52 background
background-color: #3f3f52;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #3f3f52;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(63, 63, 82, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(63, 63, 82, 0.45);
Border & gradient
Gradient panel
border: 3px solid #3f3f52;
background: linear-gradient(135deg, #3f3f52, #4C3F52);
Gradient text

Gradient headline

background: linear-gradient(90deg, #3f3f52, #503F52);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #3f3f52;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #3f3f52;
caret-color: #3f3f52;
Left rule
Pull quote or callout
border-left: 4px solid #3f3f52;
Ring + tint
Selected chip
background: #F1F1F4;
box-shadow: inset 0 0 0 2px #3f3f52;
Conic badge
68%
background: conic-gradient(#3f3f52 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #3f3f52 over white; the bottom row is the same alpha over a checkerboard, so you can see what survives on a photo or a video.

Bottom row of hexes is the flattened result over white — use those when a design tool refuses transparency, or when you need a solid fallback.

alpha in every syntaxclick to select
rgba(63, 63, 82, 0.5)
rgb(63 63 82 / 50%)
#3f3f5280
hsl(240 13% 28% / 50%)
color-mix(in srgb, #3f3f52 50%, transparent)
Alpha8-digit hexFlat on white
10%#3f3f521a#ECECEE
20%#3f3f5233#D9D9DC
40%#3f3f5266#B2B2BA
60%#3f3f5299#8C8C97
80%#3f3f52cc#656575

Gradients from #3f3f52

Six recipes, each built from this hex and shown with the exact CSS that produced it.

Elevation
Same hue, three lightnesses — safe anywhere
background: linear-gradient(135deg, #5A5A75, #3f3f52 45%, #373748);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #3f3f52, #3D3241);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #3f3f52, #52523F);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #676786 0%, #3f3f52 45%, #373748 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #F6F6F8, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #55646F 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #5A4C63 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #373748 0%, transparent 65%), #3f3f52;

Monochromatic scale

Palettes built from #3f3f52

Shades — darker

Tints — lighter

Tones — desaturated

Color harmonies

Nearest named colors

Ranked with CIEDE2000 across all 139 CSS keywords. Under ΔE 2 the eye stops telling them apart; over ΔE 10 they are plainly different colors.

#3f3f52 in the real world

Where a color in this family tends to land, and the interface roles it is usually asked to play.

Industries
TechnologyFinanceHealthcareEnterprise SaaS
Common UI roles
BackgroundsBordersBody textDividers
Print note

Converts to four-color process without much drama. Proof it anyway.

On screens

Holds up across typical panel gamma. Still worth checking on an uncalibrated laptop, where mid-tones shift most.

In dark mode

Too dim on dark surfaces at 2.04:1 — lift it to #737393 for body text, or reserve it for fills.

Explore nearby colors

Small, deliberate steps away from this hex — useful when you are hunting for the version of a colour that finally feels right.

#3f3f52, answered

What color is #3f3f52?

#3f3f52 is a dark muted blue, closest to Dark Slate Blue (ΔE2000 14.9). It sits at 240° on the hue wheel with 13% saturation and 28% lightness, which reads as cool.

What is the RGB value of #3f3f52?

rgb(63, 63, 82) — 63 red, 63 green and 82 blue out of 255, or 24.7% / 24.7% / 32.2% by channel.

What is #3f3f52 in HSL and HSV?

hsl(240, 13%, 28%) and hsv(240, 23%, 32%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #3f3f52 a light or a dark color?

It is a dark color. Relative luminance is 0.0522 and perceived brightness is 26%, so white text on it reaches 10.27:1.

Should I use black or white text on #3f3f52?

White. It scores 10.27:1 against #3f3f52, versus 2.04:1 for black — AAA at any size.

Is #3f3f52 accessible on a white background?

#3f3f52 on white scores 10.27:1, which clears AAA at every size.

What is the complementary color of #3f3f52?

#52523F sits directly opposite on the wheel. Softer options are the split-complements #52483F and #48523F, which give the same contrast with far less vibration.

What colors go well with #3f3f52?

For interface work: #F6F6F8 as the surface, #D1D1DC for borders, #646482 for secondary text, #554F3C as an accent and #373748 for hover and pressed states. For a palette, the analogous pair #3F4852 and #483F52 stays calm, while #52523F is the loudest partner.

What is #3f3f52 in CMYK for printing?

cmyk(23%, 23%, 0%, 68%). This is a screen-to-ink approximation — ask your printer for a proof before committing to a run.

Is #3f3f52 warm or cool?

Cool — it scores 62 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #463F52; nudged cooler, #3D4653.

Which Tailwind color is closest to #3f3f52?

The zinc family — its 500 step is #71717a, ΔE2000 18.3 away. That is a visible difference, so define #3f3f52 as a custom token rather than reaching for the built-in.

How do I use #3f3f52 in Tailwind CSS?

Inline it as an arbitrary value with bg-[#3f3f52] or text-[#3f3f52], or register the whole ramp under theme.extend.colors.brand so you get bg-brand-500 and friends. The generated 50–950 scale on this page is ready to paste into your config.

What is #3f3f52 with 50% opacity?

rgba(63, 63, 82, 0.5), or #3f3f5280 in eight-digit hex. Over white that composites to #9F9FA9; over black, #202029.

Is #3f3f52 a web-safe color?

No. The nearest web-safe colour is #333366, ΔE2000 10.8 away. The palette only matters for legacy displays and some email clients now.

What does the color #3f3f52 mean?

As a blue, it reads trusted, calm, competent. The default of institutions for a reason: blue is read as stable and safe across nearly every culture that has been surveyed. At this low chroma the association is faint; it behaves more like a neutral.

What gradient works with #3f3f52?

The safest is same-hue elevation: linear-gradient(135deg, #5A5A75, #3f3f52 45%, #373748). For more colour, a short hue run to #3D3241 keeps it rich without turning muddy.

Work with #3f3f52 in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #3f3f52 at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.