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cyan · cool

#3f9178

a dark, soft cyan · cool · closest name: Sea Green

Token name suggestion: Dusk Glacier

RGB
63, 145, 120
HSL
162°, 39%, 41%
CMYK
57, 0, 17, 43
Luminance
0.2266

#3f9178 is a dark soft cyan, 162° on the wheel and 80/100 on the cool side. Put black text on it (5.53:1). As text it scores 3.80:1 on white — large text only. Nearest name is Sea Green, nearest Tailwind family is teal.

hsl(162 39% 41%)rgb(63 145 120)Base step 700AA inkCool

At a glance

Every number on this page in one read: what #3f9178 is made of, how bright it looks, and which way it leans.

Hex
#3f9178
Hue
162°
cyan
Saturation
39%
soft
Lightness
41%
dark
Brightness
57%
HSV value
Perceived
48%
weighted brightness
Luminance
0.2266
WCAG relative
Temperature
Cool
80/100 cool
Color family
Cyan
Tone
Soft
Best ink
Black
5.53:1
Closest name
Sea Green
ΔE2000 8.4
Chroma
31.8
LCH, 0–130ish
OKLCH L
0.599
perceptual lightness
Tailwind
teal
500 · ΔE 12.8
Web-safe
#339966
nearest of 216
Where it sits
Hue162° of 360°
Saturation39%
Lightness41%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #3f9178.

Temperature
Warm ← → Cool80% 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
Red5%
Green89%
Blue6%

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

Every format

HEX#3f9178
HEX (8-digit)#3f9178ff
RGBrgb(63, 145, 120)
RGBArgba(63, 145, 120, 1)
HSLhsl(162, 39%, 41%)
HSV / HSBhsv(162, 57%, 57%)
HWBhwb(162 25% 43%)
CMYKcmyk(57%, 0%, 17%, 43%)
LABlab(54.7 -31.3 5.8)
LCHlch(54.7 31.8 169.5)
OKLCHoklch(0.599 0.089 170.5)
XYZ (D65)xyz(15.56, 22.66, 21.32)
Decimal4166008
Display P3color(display-p3 0.247 0.569 0.471)
Web-safe#339966

Copy-ready code

every platformclick to select
/* CSS */
color: #3f9178;
background-color: #3f9178;
/* CSS custom property */
--brand: #3f9178;
/* Tailwind (arbitrary) */
class="text-[#3f9178] bg-[#3f9178]"
/* SCSS */
$brand: #3f9178;
/* SwiftUI */
Color(red: 0.247, green: 0.569, blue: 0.471)
/* UIKit */
UIColor(red: 0.247, green: 0.569, blue: 0.471, alpha: 1)
/* Android XML */
<color name="brand">#3F9178</color>
/* Android Compose */
Color(0xFF3F9178)
/* Flutter */
Color(0xFF3F9178)
/* Python / OpenCV (BGR) */
(120, 145, 63)
/* Python / PIL (RGB) */
(63, 145, 120)
/* Java AWT */
new Color(63, 145, 120)
/* .NET */
Color.FromArgb(255, 63, 145, 120)
/* OpenGL / Unity (0–1) */
(0.2471f, 0.5686f, 0.4706f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{63,145,120}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #3f9178 85%, white);
border-color: color-mix(in oklab, #3f9178 40%, transparent);
/* theme-aware in one line */
color: light-dark(#27594A, #D4ECE5);
/* relative colour syntax */
--hover: hsl(from #3f9178 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: #F5FAF8;
  --brand-100: #EBF4F2;
  --brand-200: #D2E9E2;
  --brand-300: #B1DDD0;
  --brand-400: #8ACCB8;
  --brand-500: #63BBA0;
  --brand-600: #4AAB8D;
  --brand-700: #3f9178;
  --brand-800: #31725E;
  --brand-900: #275346;
  --brand-950: #18342C;
  --brand: #3f9178;
  --brand-ink: #000000;
  --brand-surface: #F4FAF9;
  --brand-border: #C6E6DC;
  --brand-hover: #347863;
  --brand-pressed: #295F4F;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #14241F;
    --brand-ink: #D4ECE5;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F5FAF8',
        100: '#EBF4F2',
        200: '#D2E9E2',
        300: '#B1DDD0',
        400: '#8ACCB8',
        500: '#63BBA0',
        600: '#4AAB8D',
        700: '#3f9178',
        800: '#31725E',
        900: '#275346',
        950: '#18342C',
        DEFAULT: '#3f9178',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F5FAF8,
  '100': #EBF4F2,
  '200': #D2E9E2,
  '300': #B1DDD0,
  '400': #8ACCB8,
  '500': #63BBA0,
  '600': #4AAB8D,
  '700': #3f9178,
  '800': #31725E,
  '900': #275346,
  '950': #18342C,
);
$brand-base: #3f9178;
$brand-ink: #000000;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F5FAF8", "$type": "color" },
      "100": { "$value": "#EBF4F2", "$type": "color" },
      "200": { "$value": "#D2E9E2", "$type": "color" },
      "300": { "$value": "#B1DDD0", "$type": "color" },
      "400": { "$value": "#8ACCB8", "$type": "color" },
      "500": { "$value": "#63BBA0", "$type": "color" },
      "600": { "$value": "#4AAB8D", "$type": "color" },
      "700": { "$value": "#3f9178", "$type": "color" },
      "800": { "$value": "#31725E", "$type": "color" },
      "900": { "$value": "#275346", "$type": "color" },
      "950": { "$value": "#18342C", "$type": "color" }
    },
    "brandInk": { "$value": "#000000", "$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#000000 on #3f9178 · 5.53:1
Use #000000AA at every size, AAA for large text only.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 3.80:1
AA fail · AA large pass · AAA fail
Aa
Black text · 5.53:1 · recommended
AA pass · AA large pass · AAA fail
Reading the other direction: #3f9178 as text scores 3.80:1 on white and 5.53:1 on black.
Best tinted ink on it, if plain black or white feels flat: #27594A at 2.12:1.

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
#39836C · 4.53:1
AA on white−4% L
#39836C
The quick fox
#295F4F · 7.38:1
AAA on white−14% L
#295F4F
The quick fox
#3f9178 · 5.53:1
AA on blackalready passes
#3f9178
The quick fox
#48A68A · 7.10:1
AAA on black+6% L
#48A68A

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #3F9178 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
#3f9178 on white: 3.80:1
AA ✗ fail · AA-large · AAA
Aa
#3f9178 on black: 5.53:1
AA ✓ pass · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #3f9178 as text on that neutral, and that neutral as text on #3f9178.

NeutralRatioBoth directions
White3.80:1AaAa
Slate 503.63:1AaAa
Slate 1003.46:1AaAa
Slate 2003.08:1AaAa
Slate 3002.56:1AaAa
Slate 4001.48:1AaAa
Slate 5001.25:1AaAa
Slate 6002.00:1AaAa
Slate 7002.73:1AaAa
Slate 8003.85:1AaAa
Slate 9004.70:1AaAa
Black5.53:1AaAa
Colour vision deficiency
true color
protanopia · #8D8877
deuteranopia · #817F7A
tritanopia · #14928A

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. #3f9178 is pinned to step 700; the rest hold its hue and let saturation ease off at the extremes so the pale end never turns neon.

#F5FAF8
#EBF4F2
#D2E9E2
#B1DDD0
#8ACCB8
#63BBA0
#4AAB8D
#3f9178
#31725E
#275346
#18342C
Base = 700Lightest = 50 · #F5FAF8Darkest = 950 · #18342CText step on white = 800
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 0.022 170.5);
  --brand-100: oklch(0.94 0.036 170.5);
  --brand-200: oklch(0.88 0.054 170.5);
  --brand-300: oklch(0.80 0.070 170.5);
  --brand-400: oklch(0.72 0.082 170.5);
  --brand-500: oklch(0.64 0.089 170.5);
  --brand-600: oklch(0.56 0.089 170.5);
  --brand-700: oklch(0.48 0.084 170.5);
  --brand-800: oklch(0.40 0.075 170.5);
  --brand-900: oklch(0.32 0.063 170.5);
  --brand-950: oklch(0.24 0.049 170.5);
}

Colors that work with #3f9178

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

Text on it#000000
Black wins here
Surface#F4FAF9
Tinted page background
Border#C6E6DC
Hairlines and dividers
Muted text#4B9B82
Captions on the surface
Accent#953B6D
Second voice, not a rival
Dark variant#27594A
Hover, pressed, headers
Light variant#EDF7F4
Selected rows, tints
Dark surface#14241F
Dark-mode background
Hover#347863
One step down in lightness
Pressed#295F4F
Two steps down
Disabled#8BB5A8
Chroma pulled out
Focus ring#3AAB88
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 #3f9178

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

Works well for
  • Headings from 24px up on white
  • Text and icons on dark surfaces
  • Charts, tags and secondary surfaces
  • Headers, footers and dark-mode surfaces
  • Brand accents, badges and data highlights
Use with care
  • Small text on white — under 4.5:1
  • Black text placed on it
  • Thin strokes and 1px borders — they disappear on light UI
  • Pairing with a same-lightness hue — edges vibrate
Minimum size as text on white
24px / 18.66px bold
Safe as a fill behind white type
No — use #27594A
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.

cleantechnicalfreshclinical

Cyan reads as water, air and infrastructure: cool, hygienic, engineered.

The muted chroma softens the association — it reads considered rather than loud, which suits long-form and data-heavy screens. The low lightness adds weight and formality.

Worth knowing

At high lightness it disappears into white surfaces and thin strokes vanish entirely.

Reads as
  • FormalityHigh
  • EnergyMedium
  • Weight59/100
  • TemperatureCool
  • ApproachabilityReserved

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#913F58
Analogous left#3F914F
Analogous right#3F8191
Split-complement 1#913F81
Split-complement 2#914F3F
Triadic 1#783F91
Triadic 2#91783F
Tetradic#4F3F91
On the wheel
Base+30°−30°+120°+240°+180°162°

#3f9178 sits at 162°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red24.7%
Green56.9%
Blue47.1%
R · 0–255
63
0x3f
G · 0–255
145
0x91
B · 0–255
120
0x78

CMYK percentages

Cyan56.6%
Magenta0.0%
Yellow17.2%
Key (black)43.1%

Total ink coverage is 117%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#3f9178 text on a black background

contrast 5.53:1

Card sample

#3f9178 text on a white background

contrast 3.80:1

Card sample

#3f9178 on grey

3.46:1

#3f9178 on its own surface

3.59:1

#3f9178 on its dark surface

4.25:1

CSS3 live lab

Text font color

The quick brown fox

color: #3f9178;
Background color
Panel with #3f9178 background
background-color: #3f9178;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #3f9178;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(63, 145, 120, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(63, 145, 120, 0.45);
Border & gradient
Gradient panel
border: 3px solid #3f9178;
background: linear-gradient(135deg, #3f9178, #3F7391);
Gradient text

Gradient headline

background: linear-gradient(90deg, #3f9178, #3F5F91);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #3f9178;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #3f9178;
caret-color: #3f9178;
Left rule
Pull quote or callout
border-left: 4px solid #3f9178;
Ring + tint
Selected chip
background: #EDF7F4;
box-shadow: inset 0 0 0 2px #3f9178;
Conic badge
68%
background: conic-gradient(#3f9178 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #3f9178 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, 145, 120, 0.5)
rgb(63 145 120 / 50%)
#3f917880
hsl(162 39% 41% / 50%)
color-mix(in srgb, #3f9178 50%, transparent)
Alpha8-digit hexFlat on white
10%#3f91781a#ECF4F2
20%#3f917833#D9E9E4
40%#3f917866#B2D3C9
60%#3f917899#8CBDAE
80%#3f9178cc#65A793

Gradients from #3f9178

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, #57B699, #3f9178 45%, #27594A);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #3f9178, #365D7C);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #3f9178, #913F58);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #6DBFA6 0%, #3f9178 45%, #27594A 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #F4FAF9, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #50B35B 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #488CA6 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #27594A 0%, transparent 65%), #3f9178;

Monochromatic scale

Palettes built from #3f9178

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.

#3f9178 in the real world

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

Industries
TechnologyTravelHealthcareMedia
Common UI roles
ButtonsLinksFocus statesCharts
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

Usable as-is on a dark surface at 5.53:1.

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.

#3f9178, answered

What color is #3f9178?

#3f9178 is a dark soft cyan, closest to Sea Green (ΔE2000 8.4). It sits at 162° on the hue wheel with 39% saturation and 41% lightness, which reads as cool.

What is the RGB value of #3f9178?

rgb(63, 145, 120) — 63 red, 145 green and 120 blue out of 255, or 24.7% / 56.9% / 47.1% by channel.

What is #3f9178 in HSL and HSV?

hsl(162, 39%, 41%) and hsv(162, 57%, 57%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #3f9178 a light or a dark color?

It is a mid-tone. Relative luminance is 0.2266 and perceived brightness is 48%, so black text on it reaches 5.53:1.

Should I use black or white text on #3f9178?

Black. It scores 5.53:1 against #3f9178, versus 3.80:1 for white — AA at any size.

Is #3f9178 accessible on a white background?

#3f9178 on white scores 3.80:1, which only clears AA for large text — 18.66px bold or 24px regular and up. Darken it to #39836C to reach 4.5:1, or #295F4F for 7:1.

What is the complementary color of #3f9178?

#913F58 sits directly opposite on the wheel. Softer options are the split-complements #913F81 and #914F3F, which give the same contrast with far less vibration.

What colors go well with #3f9178?

For interface work: #F4FAF9 as the surface, #C6E6DC for borders, #4B9B82 for secondary text, #953B6D as an accent and #27594A for hover and pressed states. For a palette, the analogous pair #3F914F and #3F8191 stays calm, while #913F58 is the loudest partner.

What is #3f9178 in CMYK for printing?

cmyk(57%, 0%, 17%, 43%). This is a screen-to-ink approximation — ask your printer for a proof before committing to a run.

Is #3f9178 warm or cool?

Cool — it scores 80 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #3F915A; nudged cooler, #3D8E93.

Which Tailwind color is closest to #3f9178?

The teal family — its 500 step is #14b8a6, ΔE2000 12.8 away. That is a visible difference, so define #3f9178 as a custom token rather than reaching for the built-in.

How do I use #3f9178 in Tailwind CSS?

Inline it as an arbitrary value with bg-[#3f9178] or text-[#3f9178], 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 #3f9178 with 50% opacity?

rgba(63, 145, 120, 0.5), or #3f917880 in eight-digit hex. Over white that composites to #9FC8BC; over black, #20493C.

Is #3f9178 a web-safe color?

No. The nearest web-safe colour is #339966, ΔE2000 7.4 away. The palette only matters for legacy displays and some email clients now.

What does the color #3f9178 mean?

As a cyan, it reads clean, technical, fresh. Cyan reads as water, air and infrastructure: cool, hygienic, engineered. At this moderate chroma the association is present but not shouted.

What gradient works with #3f9178?

The safest is same-hue elevation: linear-gradient(135deg, #57B699, #3f9178 45%, #27594A). For more colour, a short hue run to #365D7C keeps it rich without turning muddy.

Work with #3f9178 in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #3f9178 at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.