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red · warm

#a31739

a dark, electric red · warm · closest name: Brown

Token name suggestion: Shadow Cherry

RGB
163, 23, 57
HSL
345°, 75%, 37%
CMYK
0, 86, 65, 36
Luminance
0.0869

#a31739 is a dark electric red, 345° on the wheel and 25/100 on the cool side. Put white text on it (7.67:1). As text it scores 7.67:1 on white — safe at any size. Nearest name is Brown, nearest Tailwind family is rose.

hsl(345 75% 37%)rgb(163 23 57)Base step 700AAA inkWarm

At a glance

Every number on this page in one read: what #a31739 is made of, how bright it looks, and which way it leans.

Hex
#a31739
Hue
345°
red
Saturation
75%
electric
Lightness
37%
dark
Brightness
64%
HSV value
Perceived
36%
weighted brightness
Luminance
0.0869
WCAG relative
Temperature
Warm
25/100 cool
Color family
Red
Tone
Electric
Best ink
White
7.67:1
Closest name
Brown
ΔE2000 7.8
Chroma
58.4
LCH, 0–130ish
OKLCH L
0.465
perceptual lightness
Tailwind
rose
500 · ΔE 19.8
Web-safe
#990033
nearest of 216
Where it sits
Hue345° of 360°
Saturation75%
Lightness37%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #a31739.

Temperature
Warm ← → Cool25% cool

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

Luminance by channel
Red90%
Green7%
Blue3%

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

Every format

HEX#a31739
HEX (8-digit)#a31739ff
RGBrgb(163, 23, 57)
RGBArgba(163, 23, 57, 1)
HSLhsl(345, 75%, 37%)
HSV / HSBhsv(345, 86%, 64%)
HWBhwb(345 9% 36%)
CMYKcmyk(0%, 86%, 65%, 36%)
LABlab(35.4 55.4 18.5)
LCHlch(35.4 58.4 18.4)
OKLCHoklch(0.465 0.172 15.0)
XYZ (D65)xyz(16.15, 8.70, 4.70)
Decimal10688313
Display P3color(display-p3 0.639 0.090 0.224)
Web-safe#990033

Copy-ready code

every platformclick to select
/* CSS */
color: #a31739;
background-color: #a31739;
/* CSS custom property */
--brand: #a31739;
/* Tailwind (arbitrary) */
class="text-[#a31739] bg-[#a31739]"
/* SCSS */
$brand: #a31739;
/* SwiftUI */
Color(red: 0.639, green: 0.090, blue: 0.224)
/* UIKit */
UIColor(red: 0.639, green: 0.090, blue: 0.224, alpha: 1)
/* Android XML */
<color name="brand">#A31739</color>
/* Android Compose */
Color(0xFFA31739)
/* Flutter */
Color(0xFFA31739)
/* Python / OpenCV (BGR) */
(57, 23, 163)
/* Python / PIL (RGB) */
(163, 23, 57)
/* Java AWT */
new Color(163, 23, 57)
/* .NET */
Color.FromArgb(255, 163, 23, 57)
/* OpenGL / Unity (0–1) */
(0.6392f, 0.0902f, 0.2235f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{163,23,57}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #a31739 85%, white);
border-color: color-mix(in oklab, #a31739 40%, transparent);
/* theme-aware in one line */
color: light-dark(#701027, #EED3D9);
/* relative colour syntax */
--hover: hsl(from #a31739 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: #FCF3F5;
  --brand-100: #F9E7EB;
  --brand-200: #F4C8D3;
  --brand-300: #F19DB1;
  --brand-400: #EA6B8A;
  --brand-500: #E33A63;
  --brand-600: #D71E4B;
  --brand-700: #a31739;
  --brand-800: #8F1432;
  --brand-900: #681327;
  --brand-950: #410C19;
  --brand: #a31739;
  --brand-ink: #ffffff;
  --brand-surface: #FAF4F6;
  --brand-border: #EDC0CB;
  --brand-hover: #84132E;
  --brand-pressed: #650E23;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #241418;
    --brand-ink: #EED3D9;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#FCF3F5',
        100: '#F9E7EB',
        200: '#F4C8D3',
        300: '#F19DB1',
        400: '#EA6B8A',
        500: '#E33A63',
        600: '#D71E4B',
        700: '#a31739',
        800: '#8F1432',
        900: '#681327',
        950: '#410C19',
        DEFAULT: '#a31739',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #FCF3F5,
  '100': #F9E7EB,
  '200': #F4C8D3,
  '300': #F19DB1,
  '400': #EA6B8A,
  '500': #E33A63,
  '600': #D71E4B,
  '700': #a31739,
  '800': #8F1432,
  '900': #681327,
  '950': #410C19,
);
$brand-base: #a31739;
$brand-ink: #ffffff;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#FCF3F5", "$type": "color" },
      "100": { "$value": "#F9E7EB", "$type": "color" },
      "200": { "$value": "#F4C8D3", "$type": "color" },
      "300": { "$value": "#F19DB1", "$type": "color" },
      "400": { "$value": "#EA6B8A", "$type": "color" },
      "500": { "$value": "#E33A63", "$type": "color" },
      "600": { "$value": "#D71E4B", "$type": "color" },
      "700": { "$value": "#a31739", "$type": "color" },
      "800": { "$value": "#8F1432", "$type": "color" },
      "900": { "$value": "#681327", "$type": "color" },
      "950": { "$value": "#410C19", "$type": "color" }
    },
    "brandInk": { "$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 #a31739 · 7.67:1
Use #ffffffAAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 7.67:1 · recommended
AA pass · AA large pass · AAA pass
Aa
Black text · 2.74:1
AA fail · AA large fail · AAA fail
Reading the other direction: #a31739 as text scores 7.67:1 on white and 2.74:1 on black.
Best tinted ink on it, if plain black or white feels flat: #FCE9ED at 6.58:1.

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
#a31739 · 7.67:1
AA on whitealready passes
#a31739
The quick fox
#a31739 · 7.67:1
AAA on whitealready passes
#a31739
The quick fox
#E02250 · 4.51:1
AA on black+14% L
#E02250
The quick fox
#EB6E8C · 7.14:1
AAA on black+31% L
#EB6E8C

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #A31739 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
#a31739 on white: 7.67:1
AA ✓ pass · AA-large · AAA
Aa
#a31739 on black: 2.74:1
AA ✗ fail · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #a31739 as text on that neutral, and that neutral as text on #a31739.

NeutralRatioBoth directions
White7.67:1AaAa
Slate 507.33:1AaAa
Slate 1007.00:1AaAa
Slate 2006.22:1AaAa
Slate 3005.16:1AaAa
Slate 4002.99:1AaAa
Slate 5001.61:1AaAa
Slate 6001.01:1AaAa
Slate 7001.35:1AaAa
Slate 8001.91:1AaAa
Slate 9002.33:1AaAa
Black2.74:1AaAa
Colour vision deficiency
true color
protanopia · #434139
deuteranopia · #665D35
tritanopia · #B30027

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. #a31739 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.

#FCF3F5
#F9E7EB
#F4C8D3
#F19DB1
#EA6B8A
#E33A63
#D71E4B
#a31739
#8F1432
#681327
#410C19
Base = 700Lightest = 50 · #FCF3F5Darkest = 950 · #410C19Text 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 0.043 15.0);
  --brand-100: oklch(0.94 0.069 15.0);
  --brand-200: oklch(0.88 0.103 15.0);
  --brand-300: oklch(0.80 0.134 15.0);
  --brand-400: oklch(0.72 0.158 15.0);
  --brand-500: oklch(0.64 0.172 15.0);
  --brand-600: oklch(0.56 0.172 15.0);
  --brand-700: oklch(0.48 0.161 15.0);
  --brand-800: oklch(0.40 0.144 15.0);
  --brand-900: oklch(0.32 0.120 15.0);
  --brand-950: oklch(0.24 0.094 15.0);
}

Colors that work with #a31739

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#FAF4F6
Tinted page background
Border#EDC0CB
Hairlines and dividers
Muted text#9B4B5E
Captions on the surface
Accent#15B767
Second voice, not a rival
Dark variant#701027
Hover, pressed, headers
Light variant#FCE9ED
Selected rows, tints
Dark surface#241418
Dark-mode background
Hover#84132E
One step down in lightness
Pressed#650E23
Two steps down
Disabled#AC7E89
Chroma pulled out
Focus ring#BF0F3A
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 #a31739

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

Works well for
  • Body text and links on white
  • Primary buttons and calls to action
  • Focus rings, active and selected states
  • Headers, footers and dark-mode surfaces
  • Brand accents, badges and data highlights
Use with care
  • Text on black or near-black surfaces
  • Full-page backgrounds — tiring over long sessions
  • Black text placed on it
  • Status meaning — pair it with an icon or label, never colour alone
  • 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.

urgentappetisingboldphysical

Red arrives before the rest of the page does. It raises attention and appetite, which is why it runs food, sport and clearance pricing.

At this chroma the association is amplified — it will dominate anything placed beside it, so give it space and use it sparingly. The low lightness adds weight and formality.

Worth knowing

It is also the universal error colour. Use it as a brand accent and users may read a warning that is not there.

Reads as
  • FormalityHigh
  • EnergyHigh
  • Weight64/100
  • TemperatureWarm
  • ApproachabilityHigh

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#17A381
Analogous left#A3177F
Analogous right#A33B17
Split-complement 1#17A33B
Split-complement 2#177FA3
Triadic 1#39A317
Triadic 2#1739A3
Tetradic#7FA317
On the wheel
Base+30°−30°+120°+240°+180°345°

#a31739 sits at 345°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red63.9%
Green9.0%
Blue22.4%
R · 0–255
163
0xa3
G · 0–255
23
0x17
B · 0–255
57
0x39

CMYK percentages

Cyan0.0%
Magenta85.9%
Yellow65.0%
Key (black)36.1%

Total ink coverage is 187%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#a31739 text on a black background

contrast 2.74:1

Card sample

#a31739 text on a white background

contrast 7.67:1

Card sample

#a31739 on grey

7.00:1

#a31739 on its own surface

7.06:1

#a31739 on its dark surface

2.30:1

CSS3 live lab

Text font color

The quick brown fox

color: #a31739;
Background color
Panel with #a31739 background
background-color: #a31739;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #a31739;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(163, 23, 57, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(163, 23, 57, 0.45);
Border & gradient
Gradient panel
border: 3px solid #a31739;
background: linear-gradient(135deg, #a31739, #A35217);
Gradient text

Gradient headline

background: linear-gradient(90deg, #a31739, #A37517);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #a31739;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #a31739;
caret-color: #a31739;
Left rule
Pull quote or callout
border-left: 4px solid #a31739;
Ring + tint
Selected chip
background: #FCE9ED;
box-shadow: inset 0 0 0 2px #a31739;
Conic badge
68%
background: conic-gradient(#a31739 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #a31739 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(163, 23, 57, 0.5)
rgb(163 23 57 / 50%)
#a3173980
hsl(345 75% 37% / 50%)
color-mix(in srgb, #a31739 50%, transparent)
Alpha8-digit hexFlat on white
10%#a317391a#F6E8EB
20%#a3173933#EDD1D7
40%#a3173966#DAA2B0
60%#a3173999#C87488
80%#a31739cc#B54561

Gradients from #a31739

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, #D91F4C, #a31739 45%, #701027);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #a31739, #884F13);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #a31739, #17A381);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #E2345E 0%, #a31739 45%, #701027 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #FAF4F6, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #D01DB1 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #BE521B 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #701027 0%, transparent 65%), #a31739;

Monochromatic scale

Palettes built from #a31739

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.

#a31739 in the real world

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

Industries
Food and drinkEntertainmentRetailSport
Common UI roles
ButtonsLinksFocus statesCharts
Print note

Sits outside most CMYK gamuts — expect a duller press result, or specify a spot ink.

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 2.74:1 — lift it to #E02250 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.

#a31739, answered

What color is #a31739?

#a31739 is a dark electric red, closest to Brown (ΔE2000 7.8). It sits at 345° on the hue wheel with 75% saturation and 37% lightness, which reads as warm.

What is the RGB value of #a31739?

rgb(163, 23, 57) — 163 red, 23 green and 57 blue out of 255, or 63.9% / 9% / 22.4% by channel.

What is #a31739 in HSL and HSV?

hsl(345, 75%, 37%) and hsv(345, 86%, 64%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #a31739 a light or a dark color?

It is a dark color. Relative luminance is 0.0869 and perceived brightness is 36%, so white text on it reaches 7.67:1.

Should I use black or white text on #a31739?

White. It scores 7.67:1 against #a31739, versus 2.74:1 for black — AAA at any size.

Is #a31739 accessible on a white background?

#a31739 on white scores 7.67:1, which clears AAA at every size.

What is the complementary color of #a31739?

#17A381 sits directly opposite on the wheel. Softer options are the split-complements #17A33B and #177FA3, which give the same contrast with far less vibration.

What colors go well with #a31739?

For interface work: #FAF4F6 as the surface, #EDC0CB for borders, #9B4B5E for secondary text, #15B767 as an accent and #701027 for hover and pressed states. For a palette, the analogous pair #A3177F and #A33B17 stays calm, while #17A381 is the loudest partner.

What is #a31739 in CMYK for printing?

cmyk(0%, 86%, 65%, 36%). This is a screen-to-ink approximation — a color this saturated sits outside most CMYK gamuts and will print duller than it looks here.

Is #a31739 warm or cool?

Warm — it scores 25 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #A32817; nudged cooler, #A5156D.

Which Tailwind color is closest to #a31739?

The rose family — its 500 step is #f43f5e, ΔE2000 19.8 away. That is a visible difference, so define #a31739 as a custom token rather than reaching for the built-in.

How do I use #a31739 in Tailwind CSS?

Inline it as an arbitrary value with bg-[#a31739] or text-[#a31739], 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 #a31739 with 50% opacity?

rgba(163, 23, 57, 0.5), or #a3173980 in eight-digit hex. Over white that composites to #D18B9C; over black, #520C1D.

Is #a31739 a web-safe color?

No. The nearest web-safe colour is #990033, ΔE2000 3 away. The palette only matters for legacy displays and some email clients now.

What does the color #a31739 mean?

As a red, it reads urgent, appetising, bold. Red arrives before the rest of the page does. It raises attention and appetite, which is why it runs food, sport and clearance pricing. At this chroma the effect is amplified — it will dominate whatever sits beside it.

What gradient works with #a31739?

The safest is same-hue elevation: linear-gradient(135deg, #D91F4C, #a31739 45%, #701027). For more colour, a short hue run to #884F13 keeps it rich without turning muddy.

Work with #a31739 in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #a31739 at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.