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blue · cool

#3577aa

a dark, vivid blue · cool · closest name: Steel Blue

Token name suggestion: Forest Sapphire

RGB
53, 119, 170
HSL
206°, 53%, 44%
CMYK
69, 30, 0, 33
Luminance
0.1685

#3577aa is a dark vivid blue, 206° on the wheel and 98/100 on the cool side. Put white text on it (4.80:1). As text it scores 4.80:1 on white — safe at any size. Nearest name is Steel Blue, nearest Tailwind family is blue.

hsl(206 53% 44%)rgb(53 119 170)Base step 700AA inkCool

At a glance

Every number on this page in one read: what #3577aa is made of, how bright it looks, and which way it leans.

Hex
#3577aa
Hue
206°
blue
Saturation
53%
vivid
Lightness
44%
dark
Brightness
67%
HSV value
Perceived
44%
weighted brightness
Luminance
0.1685
WCAG relative
Temperature
Cool
98/100 cool
Color family
Blue
Tone
Vivid
Best ink
White
4.80:1
Closest name
Steel Blue
ΔE2000 4.4
Chroma
33.6
LCH, 0–130ish
OKLCH L
0.550
perceptual lightness
Tailwind
blue
500 · ΔE 9.9
Web-safe
#336699
nearest of 216
Where it sits
Hue206° of 360°
Saturation53%
Lightness44%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #3577aa.

Temperature
Warm ← → Cool98% 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
Red4%
Green78%
Blue17%

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

Every format

HEX#3577aa
HEX (8-digit)#3577aaff
RGBrgb(53, 119, 170)
RGBArgba(53, 119, 170, 1)
HSLhsl(206, 53%, 44%)
HSV / HSBhsv(206, 69%, 67%)
HWBhwb(206 21% 33%)
CMYKcmyk(69%, 30%, 0%, 33%)
LABlab(48.1 -4.1 -33.3)
LCHlch(48.1 33.6 263.0)
OKLCHoklch(0.550 0.104 244.8)
XYZ (D65)xyz(15.32, 16.85, 40.47)
Decimal3504042
Display P3color(display-p3 0.208 0.467 0.667)
Web-safe#336699

Copy-ready code

every platformclick to select
/* CSS */
color: #3577aa;
background-color: #3577aa;
/* CSS custom property */
--brand: #3577aa;
/* Tailwind (arbitrary) */
class="text-[#3577aa] bg-[#3577aa]"
/* SCSS */
$brand: #3577aa;
/* SwiftUI */
Color(red: 0.208, green: 0.467, blue: 0.667)
/* UIKit */
UIColor(red: 0.208, green: 0.467, blue: 0.667, alpha: 1)
/* Android XML */
<color name="brand">#3577AA</color>
/* Android Compose */
Color(0xFF3577AA)
/* Flutter */
Color(0xFF3577AA)
/* Python / OpenCV (BGR) */
(170, 119, 53)
/* Python / PIL (RGB) */
(53, 119, 170)
/* Java AWT */
new Color(53, 119, 170)
/* .NET */
Color.FromArgb(255, 53, 119, 170)
/* OpenGL / Unity (0–1) */
(0.2078f, 0.4667f, 0.6667f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{53,119,170}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #3577aa 85%, white);
border-color: color-mix(in oklab, #3577aa 40%, transparent);
/* theme-aware in one line */
color: light-dark(#1E4461, #D3E2EE);
/* relative colour syntax */
--hover: hsl(from #3577aa 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: #F4F8FA;
  --brand-100: #E9F0F6;
  --brand-200: #CFE0ED;
  --brand-300: #A9CBE4;
  --brand-400: #7FB0D7;
  --brand-500: #5496CA;
  --brand-600: #3A83BB;
  --brand-700: #3577aa;
  --brand-800: #27577C;
  --brand-900: #20415B;
  --brand-950: #142939;
  --brand: #3577aa;
  --brand-ink: #ffffff;
  --brand-surface: #F4F8FA;
  --brand-border: #C1D9EC;
  --brand-hover: #2C648F;
  --brand-pressed: #245173;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #141D24;
    --brand-ink: #D3E2EE;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F4F8FA',
        100: '#E9F0F6',
        200: '#CFE0ED',
        300: '#A9CBE4',
        400: '#7FB0D7',
        500: '#5496CA',
        600: '#3A83BB',
        700: '#3577aa',
        800: '#27577C',
        900: '#20415B',
        950: '#142939',
        DEFAULT: '#3577aa',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F4F8FA,
  '100': #E9F0F6,
  '200': #CFE0ED,
  '300': #A9CBE4,
  '400': #7FB0D7,
  '500': #5496CA,
  '600': #3A83BB,
  '700': #3577aa,
  '800': #27577C,
  '900': #20415B,
  '950': #142939,
);
$brand-base: #3577aa;
$brand-ink: #ffffff;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F4F8FA", "$type": "color" },
      "100": { "$value": "#E9F0F6", "$type": "color" },
      "200": { "$value": "#CFE0ED", "$type": "color" },
      "300": { "$value": "#A9CBE4", "$type": "color" },
      "400": { "$value": "#7FB0D7", "$type": "color" },
      "500": { "$value": "#5496CA", "$type": "color" },
      "600": { "$value": "#3A83BB", "$type": "color" },
      "700": { "$value": "#3577aa", "$type": "color" },
      "800": { "$value": "#27577C", "$type": "color" },
      "900": { "$value": "#20415B", "$type": "color" },
      "950": { "$value": "#142939", "$type": "color" }
    },
    "brandInk": { "$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 #3577aa · 4.80:1
Use #ffffffAA at every size, AAA for large text only.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 4.80:1 · recommended
AA pass · AA large pass · AAA fail
Aa
Black text · 4.37:1
AA fail · AA large pass · AAA fail
Reading the other direction: #3577aa as text scores 4.80:1 on white and 4.37:1 on black.
Best tinted ink on it, if plain black or white feels flat: #ECF3F9 at 4.29:1.

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
#3577aa · 4.80:1
AA on whitealready passes
#3577aa
The quick fox
#295C83 · 7.11:1
AAA on white−10% L
#295C83
The quick fox
#367AAE · 4.55:1
AA on black+1% L
#367AAE
The quick fox
#5E9DCD · 7.18:1
AAA on black+15% L
#5E9DCD

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #3577AA 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
#3577aa on white: 4.80:1
AA ✓ pass · AA-large · AAA
Aa
#3577aa on black: 4.37:1
AA ✗ fail · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #3577aa as text on that neutral, and that neutral as text on #3577aa.

NeutralRatioBoth directions
White4.80:1AaAa
Slate 504.59:1AaAa
Slate 1004.39:1AaAa
Slate 2003.90:1AaAa
Slate 3003.24:1AaAa
Slate 4001.87:1AaAa
Slate 5001.01:1AaAa
Slate 6001.58:1AaAa
Slate 7002.16:1AaAa
Slate 8003.04:1AaAa
Slate 9003.72:1AaAa
Black4.37:1AaAa
Colour vision deficiency
true color
protanopia · #6078AC
deuteranopia · #506DA9
tritanopia · #008389

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. #3577aa 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.

#F4F8FA
#E9F0F6
#CFE0ED
#A9CBE4
#7FB0D7
#5496CA
#3A83BB
#3577aa
#27577C
#20415B
#142939
Base = 700Lightest = 50 · #F4F8FADarkest = 950 · #142939Text 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 0.026 244.8);
  --brand-100: oklch(0.94 0.042 244.8);
  --brand-200: oklch(0.88 0.062 244.8);
  --brand-300: oklch(0.80 0.081 244.8);
  --brand-400: oklch(0.72 0.096 244.8);
  --brand-500: oklch(0.64 0.104 244.8);
  --brand-600: oklch(0.56 0.104 244.8);
  --brand-700: oklch(0.48 0.098 244.8);
  --brand-800: oklch(0.40 0.087 244.8);
  --brand-900: oklch(0.32 0.073 244.8);
  --brand-950: oklch(0.24 0.057 244.8);
}

Colors that work with #3577aa

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#F4F8FA
Tinted page background
Border#C1D9EC
Hairlines and dividers
Muted text#4B789B
Captions on the surface
Accent#AE4830
Second voice, not a rival
Dark variant#1E4461
Hover, pressed, headers
Light variant#ECF3F9
Selected rows, tints
Dark surface#141D24
Dark-mode background
Hover#2C648F
One step down in lightness
Pressed#245173
Two steps down
Disabled#94AABB
Chroma pulled out
Focus ring#2E83C6
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 #3577aa

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
  • Full-page backgrounds — tiring over long sessions
  • 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.

This is a confident chroma: strong enough to lead a brand, restrained enough to live in an interface all day. 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-high
  • Weight56/100
  • 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#AA6835
Analogous left#35AAA3
Analogous right#353CAA
Split-complement 1#AA353C
Split-complement 2#AAA335
Triadic 1#AA3577
Triadic 2#77AA35
Tetradic#A335AA
On the wheel
Base+30°−30°+120°+240°+180°206°

#3577aa sits at 206°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red20.8%
Green46.7%
Blue66.7%
R · 0–255
53
0x35
G · 0–255
119
0x77
B · 0–255
170
0xaa

CMYK percentages

Cyan68.8%
Magenta30.0%
Yellow0.0%
Key (black)33.3%

Total ink coverage is 132%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#3577aa text on a black background

contrast 4.37:1

Card sample

#3577aa text on a white background

contrast 4.80:1

Card sample

#3577aa on grey

4.39:1

#3577aa on its own surface

4.50:1

#3577aa on its dark surface

3.55:1

CSS3 live lab

Text font color

The quick brown fox

color: #3577aa;
Background color
Panel with #3577aa background
background-color: #3577aa;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #3577aa;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(53, 119, 170, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(53, 119, 170, 0.45);
Border & gradient
Gradient panel
border: 3px solid #3577aa;
background: linear-gradient(135deg, #3577aa, #4135AA);
Gradient text

Gradient headline

background: linear-gradient(90deg, #3577aa, #5E35AA);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #3577aa;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #3577aa;
caret-color: #3577aa;
Left rule
Pull quote or callout
border-left: 4px solid #3577aa;
Ring + tint
Selected chip
background: #ECF3F9;
box-shadow: inset 0 0 0 2px #3577aa;
Conic badge
68%
background: conic-gradient(#3577aa 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #3577aa 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(53, 119, 170, 0.5)
rgb(53 119 170 / 50%)
#3577aa80
hsl(206 53% 44% / 50%)
color-mix(in srgb, #3577aa 50%, transparent)
Alpha8-digit hexFlat on white
10%#3577aa1a#EBF1F7
20%#3577aa33#D7E4EE
40%#3577aa66#AEC9DD
60%#3577aa99#86ADCC
80%#3577aacc#5D92BB

Gradients from #3577aa

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, #5396C9, #3577aa 45%, #1E4461);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #3577aa, #412E93);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #3577aa, #AA6835);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #6AA4D1 0%, #3577aa 45%, #1E4461 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #F4F8FA, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #4BC7B5 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #3F3CC1 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #1E4461 0%, transparent 65%), #3577aa;

Monochromatic scale

Palettes built from #3577aa

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.

#3577aa 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

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 4.37:1 — lift it to #367AAE 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.

#3577aa, answered

What color is #3577aa?

#3577aa is a dark vivid blue, closest to Steel Blue (ΔE2000 4.4). It sits at 206° on the hue wheel with 53% saturation and 44% lightness, which reads as cool.

What is the RGB value of #3577aa?

rgb(53, 119, 170) — 53 red, 119 green and 170 blue out of 255, or 20.8% / 46.7% / 66.7% by channel.

What is #3577aa in HSL and HSV?

hsl(206, 53%, 44%) and hsv(206, 69%, 67%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #3577aa a light or a dark color?

It is a dark color. Relative luminance is 0.1685 and perceived brightness is 44%, so white text on it reaches 4.80:1.

Should I use black or white text on #3577aa?

White. It scores 4.80:1 against #3577aa, versus 4.37:1 for black — AA at any size.

Is #3577aa accessible on a white background?

#3577aa on white scores 4.80:1, which clears AA at every size but not AAA.

What is the complementary color of #3577aa?

#AA6835 sits directly opposite on the wheel. Softer options are the split-complements #AA353C and #AAA335, which give the same contrast with far less vibration.

What colors go well with #3577aa?

For interface work: #F4F8FA as the surface, #C1D9EC for borders, #4B789B for secondary text, #AE4830 as an accent and #1E4461 for hover and pressed states. For a palette, the analogous pair #35AAA3 and #353CAA stays calm, while #AA6835 is the loudest partner.

What is #3577aa in CMYK for printing?

cmyk(69%, 30%, 0%, 33%). This is a screen-to-ink approximation — ask your printer for a proof before committing to a run.

Is #3577aa warm or cool?

Cool — it scores 98 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #354CAA; nudged cooler, #2D6398.

Which Tailwind color is closest to #3577aa?

The blue family — its 500 step is #3b82f6, ΔE2000 9.9 away. That is a visible difference, so define #3577aa as a custom token rather than reaching for the built-in.

How do I use #3577aa in Tailwind CSS?

Inline it as an arbitrary value with bg-[#3577aa] or text-[#3577aa], 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 #3577aa with 50% opacity?

rgba(53, 119, 170, 0.5), or #3577aa80 in eight-digit hex. Over white that composites to #9ABBD5; over black, #1B3C55.

Is #3577aa a web-safe color?

No. The nearest web-safe colour is #336699, ΔE2000 6.5 away. The palette only matters for legacy displays and some email clients now.

What does the color #3577aa 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 chroma the effect is amplified — it will dominate whatever sits beside it.

What gradient works with #3577aa?

The safest is same-hue elevation: linear-gradient(135deg, #5396C9, #3577aa 45%, #1E4461). For more colour, a short hue run to #412E93 keeps it rich without turning muddy.

Work with #3577aa in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #3577aa at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.