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blue · cool

#121c21

a deep, soft blue · cool · closest name: Black

Token name suggestion: Abyss Harbour

RGB
18, 28, 33
HSL
200°, 29%, 10%
CMYK
46, 15, 0, 87
Luminance
0.0107

#121c21 is a deep soft blue, 200° on the wheel and 89/100 on the cool side. Put white text on it (17.30:1). As text it scores 17.30:1 on white — safe at any size. Nearest name is Black, nearest Tailwind family is gray.

hsl(200 29% 10%)rgb(18 28 33)Base step 950AAA inkCool

At a glance

Every number on this page in one read: what #121c21 is made of, how bright it looks, and which way it leans.

Hex
#121c21
Hue
200°
blue
Saturation
29%
soft
Lightness
10%
deep
Brightness
13%
HSV value
Perceived
10%
weighted brightness
Luminance
0.0107
WCAG relative
Temperature
Cool
89/100 cool
Color family
Blue
Tone
Soft
Best ink
White
17.30:1
Closest name
Black
ΔE2000 8
Chroma
5.7
LCH, 0–130ish
OKLCH L
0.219
perceptual lightness
Tailwind
gray
500 · ΔE 29.7
Web-safe
#003333
nearest of 216
Where it sits
Hue200° of 360°
Saturation29%
Lightness10%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #121c21.

Temperature
Warm ← → Cool89% 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
Red12%
Green78%
Blue10%

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

Every format

HEX#121c21
HEX (8-digit)#121c21ff
RGBrgb(18, 28, 33)
RGBArgba(18, 28, 33, 1)
HSLhsl(200, 29%, 10%)
HSV / HSBhsv(200, 45%, 13%)
HWBhwb(200 7% 87%)
CMYKcmyk(46%, 15%, 0%, 87%)
LABlab(9.6 -2.9 -4.9)
LCHlch(9.6 5.7 239.7)
OKLCHoklch(0.219 0.017 230.2)
XYZ (D65)xyz(0.94, 1.07, 1.60)
Decimal1186849
Display P3color(display-p3 0.071 0.110 0.129)
Web-safe#003333

Copy-ready code

every platformclick to select
/* CSS */
color: #121c21;
background-color: #121c21;
/* CSS custom property */
--brand: #121c21;
/* Tailwind (arbitrary) */
class="text-[#121c21] bg-[#121c21]"
/* SCSS */
$brand: #121c21;
/* SwiftUI */
Color(red: 0.071, green: 0.110, blue: 0.129)
/* UIKit */
UIColor(red: 0.071, green: 0.110, blue: 0.129, alpha: 1)
/* Android XML */
<color name="brand">#121C21</color>
/* Android Compose */
Color(0xFF121C21)
/* Flutter */
Color(0xFF121C21)
/* Python / OpenCV (BGR) */
(33, 28, 18)
/* Python / PIL (RGB) */
(18, 28, 33)
/* Java AWT */
new Color(18, 28, 33)
/* .NET */
Color.FromArgb(255, 18, 28, 33)
/* OpenGL / Unity (0–1) */
(0.0706f, 0.1098f, 0.1294f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{18,28,33}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #121c21 85%, white);
border-color: color-mix(in oklab, #121c21 40%, transparent);
/* theme-aware in one line */
color: light-dark(#2D4652, #D7E3E9);
/* relative colour syntax */
--hover: hsl(from #121c21 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: #F6F8F9;
  --brand-100: #ECF1F3;
  --brand-200: #D5E1E6;
  --brand-300: #B6CCD7;
  --brand-400: #92B3C4;
  --brand-500: #6E9AB0;
  --brand-600: #56869E;
  --brand-700: #487084;
  --brand-800: #3A5A6A;
  --brand-900: #2D434E;
  --brand-950: #121c21;
  --brand: #121c21;
  --brand-ink: #ffffff;
  --brand-surface: #F5F8FA;
  --brand-border: #CADAE2;
  --brand-hover: #05080A;
  --brand-pressed: #000000;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #141F24;
    --brand-ink: #D7E3E9;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F6F8F9',
        100: '#ECF1F3',
        200: '#D5E1E6',
        300: '#B6CCD7',
        400: '#92B3C4',
        500: '#6E9AB0',
        600: '#56869E',
        700: '#487084',
        800: '#3A5A6A',
        900: '#2D434E',
        950: '#121c21',
        DEFAULT: '#121c21',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F6F8F9,
  '100': #ECF1F3,
  '200': #D5E1E6,
  '300': #B6CCD7,
  '400': #92B3C4,
  '500': #6E9AB0,
  '600': #56869E,
  '700': #487084,
  '800': #3A5A6A,
  '900': #2D434E,
  '950': #121c21,
);
$brand-base: #121c21;
$brand-ink: #ffffff;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F6F8F9", "$type": "color" },
      "100": { "$value": "#ECF1F3", "$type": "color" },
      "200": { "$value": "#D5E1E6", "$type": "color" },
      "300": { "$value": "#B6CCD7", "$type": "color" },
      "400": { "$value": "#92B3C4", "$type": "color" },
      "500": { "$value": "#6E9AB0", "$type": "color" },
      "600": { "$value": "#56869E", "$type": "color" },
      "700": { "$value": "#487084", "$type": "color" },
      "800": { "$value": "#3A5A6A", "$type": "color" },
      "900": { "$value": "#2D434E", "$type": "color" },
      "950": { "$value": "#121c21", "$type": "color" }
    },
    "brandInk": { "$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 #121c21 · 17.30:1
Use #ffffffAAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 17.30:1 · recommended
AA pass · AA large pass · AAA pass
Aa
Black text · 1.21:1
AA fail · AA large fail · AAA fail
Reading the other direction: #121c21 as text scores 17.30:1 on white and 1.21:1 on black.
Best tinted ink on it, if plain black or white feels flat: #EFF3F6 at 15.51:1.

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
#121c21 · 17.30:1
AA on whitealready passes
#121c21
The quick fox
#121c21 · 17.30:1
AAA on whitealready passes
#121c21
The quick fox
#4F7B91 · 4.57:1
AA on black+34% L
#4F7B91
The quick fox
#719CB2 · 7.10:1
AAA on black+47% L
#719CB2

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #121C21 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
#121c21 on white: 17.30:1
AA ✓ pass · AA-large · AAA
Aa
#121c21 on black: 1.21:1
AA ✗ fail · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #121c21 as text on that neutral, and that neutral as text on #121c21.

NeutralRatioBoth directions
White17.30:1AaAa
Slate 5016.54:1AaAa
Slate 10015.79:1AaAa
Slate 20014.03:1AaAa
Slate 30011.65:1AaAa
Slate 4006.75:1AaAa
Slate 5003.64:1AaAa
Slate 6002.28:1AaAa
Slate 7001.67:1AaAa
Slate 8001.18:1AaAa
Slate 9001.03:1AaAa
Black1.21:1AaAa
Colour vision deficiency
true color
protanopia · #1A1C21
deuteranopia · #171A21
tritanopia · #0D1D1E

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. #121c21 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.

#F6F8F9
#ECF1F3
#D5E1E6
#B6CCD7
#92B3C4
#6E9AB0
#56869E
#487084
#3A5A6A
#2D434E
#121c21
Base = 950Lightest = 50 · #F6F8F9Darkest = 950 · #121c21Text step on white = 700
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 0.004 230.2);
  --brand-100: oklch(0.94 0.007 230.2);
  --brand-200: oklch(0.88 0.010 230.2);
  --brand-300: oklch(0.80 0.014 230.2);
  --brand-400: oklch(0.72 0.016 230.2);
  --brand-500: oklch(0.64 0.017 230.2);
  --brand-600: oklch(0.56 0.017 230.2);
  --brand-700: oklch(0.48 0.016 230.2);
  --brand-800: oklch(0.40 0.015 230.2);
  --brand-900: oklch(0.32 0.012 230.2);
  --brand-950: oklch(0.24 0.010 230.2);
}

Colors that work with #121c21

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#F5F8FA
Tinted page background
Border#CADAE2
Hairlines and dividers
Muted text#517E94
Captions on the surface
Accent#221211
Second voice, not a rival
Dark variant#2D4652
Hover, pressed, headers
Light variant#EFF3F6
Selected rows, tints
Dark surface#141F24
Dark-mode background
Hover#05080A
One step down in lightness
Pressed#000000
Two steps down
Disabled#405864
Chroma pulled out
Focus ring#162832
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 #121c21

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
  • 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.

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

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

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#211712
Analogous left#12211E
Analogous right#121521
Split-complement 1#211215
Split-complement 2#211E12
Triadic 1#21121C
Triadic 2#1C2112
Tetradic#1E1221
On the wheel
Base+30°−30°+120°+240°+180°200°

#121c21 sits at 200°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red7.1%
Green11.0%
Blue12.9%
R · 0–255
18
0x12
G · 0–255
28
0x1c
B · 0–255
33
0x21

CMYK percentages

Cyan45.5%
Magenta15.2%
Yellow0.0%
Key (black)87.1%

Total ink coverage is 148%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#121c21 text on a black background

contrast 1.21:1

Card sample

#121c21 text on a white background

contrast 17.30:1

Card sample

#121c21 on grey

15.79:1

#121c21 on its own surface

16.22:1

#121c21 on its dark surface

1.03:1

CSS3 live lab

Text font color

The quick brown fox

color: #121c21;
Background color
Panel with #121c21 background
background-color: #121c21;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #121c21;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(18, 28, 33, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(18, 28, 33, 0.45);
Border & gradient
Gradient panel
border: 3px solid #121c21;
background: linear-gradient(135deg, #121c21, #121221);
Gradient text

Gradient headline

background: linear-gradient(90deg, #121c21, #161221);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #121c21;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #121c21;
caret-color: #121c21;
Left rule
Pull quote or callout
border-left: 4px solid #121c21;
Ring + tint
Selected chip
background: #EFF3F6;
box-shadow: inset 0 0 0 2px #121c21;
Conic badge
68%
background: conic-gradient(#121c21 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #121c21 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(18, 28, 33, 0.5)
rgb(18 28 33 / 50%)
#121c2180
hsl(200 29% 10% / 50%)
color-mix(in srgb, #121c21 50%, transparent)
Alpha8-digit hexFlat on white
10%#121c211a#E7E8E9
20%#121c2133#D0D2D3
40%#121c2166#A0A4A6
60%#121c2199#71777A
80%#121c21cc#41494D

Gradients from #121c21

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, #283E49, #121c21 45%, #2D4652);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #121c21, #08070D);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #121c21, #211712);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #324E5C 0%, #121c21 45%, #2D4652 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #F5F8FA, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #24423A 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #1D1F35 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #2D4652 0%, transparent 65%), #121c21;

Monochromatic scale

Palettes built from #121c21

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.

#121c21 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
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 1.21:1 — lift it to #4F7B91 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.

#121c21, answered

What color is #121c21?

#121c21 is a deep soft blue, closest to Black (ΔE2000 8). It sits at 200° on the hue wheel with 29% saturation and 10% lightness, which reads as cool.

What is the RGB value of #121c21?

rgb(18, 28, 33) — 18 red, 28 green and 33 blue out of 255, or 7.1% / 11% / 12.9% by channel.

What is #121c21 in HSL and HSV?

hsl(200, 29%, 10%) and hsv(200, 45%, 13%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #121c21 a light or a dark color?

It is a dark color. Relative luminance is 0.0107 and perceived brightness is 10%, so white text on it reaches 17.30:1.

Should I use black or white text on #121c21?

White. It scores 17.30:1 against #121c21, versus 1.21:1 for black — AAA at any size.

Is #121c21 accessible on a white background?

#121c21 on white scores 17.30:1, which clears AAA at every size.

What is the complementary color of #121c21?

#211712 sits directly opposite on the wheel. Softer options are the split-complements #211215 and #211E12, which give the same contrast with far less vibration.

What colors go well with #121c21?

For interface work: #F5F8FA as the surface, #CADAE2 for borders, #517E94 for secondary text, #221211 as an accent and #2D4652 for hover and pressed states. For a palette, the analogous pair #12211E and #121521 stays calm, while #211712 is the loudest partner.

What is #121c21 in CMYK for printing?

cmyk(46%, 15%, 0%, 87%). This is a screen-to-ink approximation — ask your printer for a proof before committing to a run.

Is #121c21 warm or cool?

Cool — it scores 89 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #122120; nudged cooler, #111922.

Which Tailwind color is closest to #121c21?

The gray family — its 500 step is #6b7280, ΔE2000 29.7 away. That is a visible difference, so define #121c21 as a custom token rather than reaching for the built-in.

How do I use #121c21 in Tailwind CSS?

Inline it as an arbitrary value with bg-[#121c21] or text-[#121c21], 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 #121c21 with 50% opacity?

rgba(18, 28, 33, 0.5), or #121c2180 in eight-digit hex. Over white that composites to #898E90; over black, #090E11.

Is #121c21 a web-safe color?

No. The nearest web-safe colour is #003333, ΔE2000 13.2 away. The palette only matters for legacy displays and some email clients now.

What does the color #121c21 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 moderate chroma the association is present but not shouted.

What gradient works with #121c21?

The safest is same-hue elevation: linear-gradient(135deg, #283E49, #121c21 45%, #2D4652). For more colour, a short hue run to #08070D keeps it rich without turning muddy.

Work with #121c21 in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #121c21 at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.