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cyan · cool

#0f2521

a deep, soft cyan · cool · closest name: Dark Slate Gray

Token name suggestion: Abyss Glacier

RGB
15, 37, 33
HSL
169°, 42%, 10%
CMYK
60, 0, 11, 86
Luminance
0.0153

#0f2521 is a deep soft cyan, 169° on the wheel and 83/100 on the cool side. Put white text on it (16.07:1). As text it scores 16.07:1 on white — safe at any size. Nearest name is Dark Slate Gray, nearest Tailwind family is neutral.

hsl(169 42% 10%)rgb(15 37 33)Base step 950AAA inkCool

At a glance

Every number on this page in one read: what #0f2521 is made of, how bright it looks, and which way it leans.

Hex
#0f2521
Hue
169°
cyan
Saturation
42%
soft
Lightness
10%
deep
Brightness
15%
HSV value
Perceived
12%
weighted brightness
Luminance
0.0153
WCAG relative
Temperature
Cool
83/100 cool
Color family
Cyan
Tone
Soft
Best ink
White
16.07:1
Closest name
Dark Slate Gray
ΔE2000 13.4
Chroma
10.0
LCH, 0–130ish
OKLCH L
0.245
perceptual lightness
Tailwind
neutral
500 · ΔE 29.9
Web-safe
#003333
nearest of 216
Where it sits
Hue169° of 360°
Saturation42%
Lightness10%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #0f2521.

Temperature
Warm ← → Cool83% 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
Red7%
Green86%
Blue7%

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

Every format

HEX#0f2521
HEX (8-digit)#0f2521ff
RGBrgb(15, 37, 33)
RGBArgba(15, 37, 33, 1)
HSLhsl(169, 42%, 10%)
HSV / HSBhsv(169, 59%, 15%)
HWBhwb(169 6% 85%)
CMYKcmyk(60%, 0%, 11%, 86%)
LABlab(12.8 -10.0 -0.0)
LCHlch(12.8 10.0 180.2)
OKLCHoklch(0.245 0.029 180.5)
XYZ (D65)xyz(1.13, 1.53, 1.68)
Decimal992545
Display P3color(display-p3 0.059 0.145 0.129)
Web-safe#003333

Copy-ready code

every platformclick to select
/* CSS */
color: #0f2521;
background-color: #0f2521;
/* CSS custom property */
--brand: #0f2521;
/* Tailwind (arbitrary) */
class="text-[#0f2521] bg-[#0f2521]"
/* SCSS */
$brand: #0f2521;
/* SwiftUI */
Color(red: 0.059, green: 0.145, blue: 0.129)
/* UIKit */
UIColor(red: 0.059, green: 0.145, blue: 0.129, alpha: 1)
/* Android XML */
<color name="brand">#0F2521</color>
/* Android Compose */
Color(0xFF0F2521)
/* Flutter */
Color(0xFF0F2521)
/* Python / OpenCV (BGR) */
(33, 37, 15)
/* Python / PIL (RGB) */
(15, 37, 33)
/* Java AWT */
new Color(15, 37, 33)
/* .NET */
Color.FromArgb(255, 15, 37, 33)
/* OpenGL / Unity (0–1) */
(0.0588f, 0.1451f, 0.1294f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{15,37,33}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #0f2521 85%, white);
border-color: color-mix(in oklab, #0f2521 40%, transparent);
/* theme-aware in one line */
color: light-dark(#255B51, #D3EDE9);
/* relative colour syntax */
--hover: hsl(from #0f2521 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: #F5FAF9;
  --brand-100: #EBF5F3;
  --brand-200: #D2EAE6;
  --brand-300: #AFDFD6;
  --brand-400: #87CEC2;
  --brand-500: #5FBEAD;
  --brand-600: #47AE9B;
  --brand-700: #3B9181;
  --brand-800: #2F7468;
  --brand-900: #25554C;
  --brand-950: #0f2521;
  --brand: #0f2521;
  --brand-ink: #ffffff;
  --brand-surface: #F4FAF9;
  --brand-border: #C5E7E1;
  --brand-hover: #050C0A;
  --brand-pressed: #000000;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #142421;
    --brand-ink: #D3EDE9;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F5FAF9',
        100: '#EBF5F3',
        200: '#D2EAE6',
        300: '#AFDFD6',
        400: '#87CEC2',
        500: '#5FBEAD',
        600: '#47AE9B',
        700: '#3B9181',
        800: '#2F7468',
        900: '#25554C',
        950: '#0f2521',
        DEFAULT: '#0f2521',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F5FAF9,
  '100': #EBF5F3,
  '200': #D2EAE6,
  '300': #AFDFD6,
  '400': #87CEC2,
  '500': #5FBEAD,
  '600': #47AE9B,
  '700': #3B9181,
  '800': #2F7468,
  '900': #25554C,
  '950': #0f2521,
);
$brand-base: #0f2521;
$brand-ink: #ffffff;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F5FAF9", "$type": "color" },
      "100": { "$value": "#EBF5F3", "$type": "color" },
      "200": { "$value": "#D2EAE6", "$type": "color" },
      "300": { "$value": "#AFDFD6", "$type": "color" },
      "400": { "$value": "#87CEC2", "$type": "color" },
      "500": { "$value": "#5FBEAD", "$type": "color" },
      "600": { "$value": "#47AE9B", "$type": "color" },
      "700": { "$value": "#3B9181", "$type": "color" },
      "800": { "$value": "#2F7468", "$type": "color" },
      "900": { "$value": "#25554C", "$type": "color" },
      "950": { "$value": "#0f2521", "$type": "color" }
    },
    "brandInk": { "$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 #0f2521 · 16.07:1
Use #ffffffAAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 16.07:1 · recommended
AA pass · AA large pass · AAA pass
Aa
Black text · 1.31:1
AA fail · AA large fail · AAA fail
Reading the other direction: #0f2521 as text scores 16.07:1 on white and 1.31:1 on black.
Best tinted ink on it, if plain black or white feels flat: #EDF8F6 at 14.81:1.

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
#0f2521 · 16.07:1
AA on whitealready passes
#0f2521
The quick fox
#0f2521 · 16.07:1
AAA on whitealready passes
#0f2521
The quick fox
#358375 · 4.65:1
AA on black+26% L
#358375
The quick fox
#44A896 · 7.29:1
AAA on black+36% L
#44A896

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #0F2521 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
#0f2521 on white: 16.07:1
AA ✓ pass · AA-large · AAA
Aa
#0f2521 on black: 1.31:1
AA ✗ fail · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #0f2521 as text on that neutral, and that neutral as text on #0f2521.

NeutralRatioBoth directions
White16.07:1AaAa
Slate 5015.36:1AaAa
Slate 10014.67:1AaAa
Slate 20013.03:1AaAa
Slate 30010.82:1AaAa
Slate 4006.27:1AaAa
Slate 5003.38:1AaAa
Slate 6002.12:1AaAa
Slate 7001.55:1AaAa
Slate 8001.10:1AaAa
Slate 9001.11:1AaAa
Black1.31:1AaAa
Colour vision deficiency
true color
protanopia · #232321
deuteranopia · #202021
tritanopia · #062624

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. #0f2521 is pinned to step 950; the rest hold its hue and let saturation ease off at the extremes so the pale end never turns neon.

#F5FAF9
#EBF5F3
#D2EAE6
#AFDFD6
#87CEC2
#5FBEAD
#47AE9B
#3B9181
#2F7468
#25554C
#0f2521
Base = 950Lightest = 50 · #F5FAF9Darkest = 950 · #0f2521Text 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 0.007 180.5);
  --brand-100: oklch(0.94 0.012 180.5);
  --brand-200: oklch(0.88 0.018 180.5);
  --brand-300: oklch(0.80 0.023 180.5);
  --brand-400: oklch(0.72 0.027 180.5);
  --brand-500: oklch(0.64 0.029 180.5);
  --brand-600: oklch(0.56 0.029 180.5);
  --brand-700: oklch(0.48 0.028 180.5);
  --brand-800: oklch(0.40 0.025 180.5);
  --brand-900: oklch(0.32 0.021 180.5);
  --brand-950: oklch(0.24 0.016 180.5);
}

Colors that work with #0f2521

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#F4FAF9
Tinted page background
Border#C5E7E1
Hairlines and dividers
Muted text#4B9B8C
Captions on the surface
Accent#260E18
Second voice, not a rival
Dark variant#255B51
Hover, pressed, headers
Light variant#EDF8F6
Selected rows, tints
Dark surface#142421
Dark-mode background
Hover#050C0A
One step down in lightness
Pressed#000000
Two steps down
Disabled#40645E
Chroma pulled out
Focus ring#113730
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 #0f2521

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

Works well for
  • Body text and links on white
  • Charts, tags and secondary 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
  • Thin strokes and 1px borders — they disappear on light UI
  • 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.

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
  • Weight90/100
  • 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#250F13
Analogous left#0F2516
Analogous right#0F1E25
Split-complement 1#250F1E
Split-complement 2#25160F
Triadic 1#210F25
Triadic 2#25210F
Tetradic#160F25
On the wheel
Base+30°−30°+120°+240°+180°169°

#0f2521 sits at 169°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red5.9%
Green14.5%
Blue12.9%
R · 0–255
15
0x0f
G · 0–255
37
0x25
B · 0–255
33
0x21

CMYK percentages

Cyan59.5%
Magenta0.0%
Yellow10.8%
Key (black)85.5%

Total ink coverage is 156%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#0f2521 text on a black background

contrast 1.31:1

Card sample

#0f2521 text on a white background

contrast 16.07:1

Card sample

#0f2521 on grey

14.67:1

#0f2521 on its own surface

15.22:1

#0f2521 on its dark surface

1.00:1

CSS3 live lab

Text font color

The quick brown fox

color: #0f2521;
Background color
Panel with #0f2521 background
background-color: #0f2521;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #0f2521;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(15, 37, 33, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(15, 37, 33, 0.45);
Border & gradient
Gradient panel
border: 3px solid #0f2521;
background: linear-gradient(135deg, #0f2521, #0F1A25);
Gradient text

Gradient headline

background: linear-gradient(90deg, #0f2521, #0F1525);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #0f2521;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #0f2521;
caret-color: #0f2521;
Left rule
Pull quote or callout
border-left: 4px solid #0f2521;
Ring + tint
Selected chip
background: #EDF8F6;
box-shadow: inset 0 0 0 2px #0f2521;
Conic badge
68%
background: conic-gradient(#0f2521 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #0f2521 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(15, 37, 33, 0.5)
rgb(15 37 33 / 50%)
#0f252180
hsl(169 42% 10% / 50%)
color-mix(in srgb, #0f2521 50%, transparent)
Alpha8-digit hexFlat on white
10%#0f25211a#E7E9E9
20%#0f252133#CFD3D3
40%#0f252166#9FA8A6
60%#0f252199#6F7C7A
80%#0f2521cc#3F514D

Gradients from #0f2521

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, #215148, #0f2521 45%, #255B51);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #0f2521, #060A0F);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #0f2521, #250F13);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #29665B 0%, #0f2521 45%, #255B51 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%, #1E4928 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #182D3B 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #255B51 0%, transparent 65%), #0f2521;

Monochromatic scale

Palettes built from #0f2521

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.

#0f2521 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

Very dark values collapse into each other on cheap panels — leave more lightness between your darkest steps than the numbers suggest.

In dark mode

Too dim on dark surfaces at 1.31:1 — lift it to #358375 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.

#0f2521, answered

What color is #0f2521?

#0f2521 is a deep soft cyan, closest to Dark Slate Gray (ΔE2000 13.4). It sits at 169° on the hue wheel with 42% saturation and 10% lightness, which reads as cool.

What is the RGB value of #0f2521?

rgb(15, 37, 33) — 15 red, 37 green and 33 blue out of 255, or 5.9% / 14.5% / 12.9% by channel.

What is #0f2521 in HSL and HSV?

hsl(169, 42%, 10%) and hsv(169, 59%, 15%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #0f2521 a light or a dark color?

It is a dark color. Relative luminance is 0.0153 and perceived brightness is 12%, so white text on it reaches 16.07:1.

Should I use black or white text on #0f2521?

White. It scores 16.07:1 against #0f2521, versus 1.31:1 for black — AAA at any size.

Is #0f2521 accessible on a white background?

#0f2521 on white scores 16.07:1, which clears AAA at every size.

What is the complementary color of #0f2521?

#250F13 sits directly opposite on the wheel. Softer options are the split-complements #250F1E and #25160F, which give the same contrast with far less vibration.

What colors go well with #0f2521?

For interface work: #F4FAF9 as the surface, #C5E7E1 for borders, #4B9B8C for secondary text, #260E18 as an accent and #255B51 for hover and pressed states. For a palette, the analogous pair #0F2516 and #0F1E25 stays calm, while #250F13 is the loudest partner.

What is #0f2521 in CMYK for printing?

cmyk(60%, 0%, 11%, 86%). This is a screen-to-ink approximation — ask your printer for a proof before committing to a run.

Is #0f2521 warm or cool?

Cool — it scores 83 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #0F2519; nudged cooler, #0E2126.

Which Tailwind color is closest to #0f2521?

The neutral family — its 500 step is #737373, ΔE2000 29.9 away. That is a visible difference, so define #0f2521 as a custom token rather than reaching for the built-in.

How do I use #0f2521 in Tailwind CSS?

Inline it as an arbitrary value with bg-[#0f2521] or text-[#0f2521], 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 #0f2521 with 50% opacity?

rgba(15, 37, 33, 0.5), or #0f252180 in eight-digit hex. Over white that composites to #879290; over black, #081311.

Is #0f2521 a web-safe color?

No. The nearest web-safe colour is #003333, ΔE2000 6.5 away. The palette only matters for legacy displays and some email clients now.

What does the color #0f2521 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 #0f2521?

The safest is same-hue elevation: linear-gradient(135deg, #215148, #0f2521 45%, #255B51). For more colour, a short hue run to #060A0F keeps it rich without turning muddy.

Work with #0f2521 in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #0f2521 at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.