What color is #255366?

#255366 is a dark cyan-blue. In RGB it is rgb(37, 83, 102), and in HSL hsl(198, 47%, 27%).

Is #255366 accessible as text?

On white, #255366 has a contrast ratio of 8.37:1 (passes WCAG AA for body text); on black it is 2.51:1 (fails). For text placed on #255366, use white for the best readability.

What is the closest Tailwind color to #255366?

The nearest Tailwind CSS token is cyan-900 (#104E64).

What colors go well with #255366?

#255366 pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #653824. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #255366 below.

Is #255366 good for buttons?

#255366 works well for buttons and highlights, but use white text on #255366 — black text only reaches 2.51:1, below the 4.5:1 needed for normal-size labels.

Is #255366 the same as CSS darkslategray?

No — #255366 is not the CSS named color darkslategray, but darkslategray (#2F4F4F) is the closest CSS named color.

#255366 Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #255366

Not just a swatch — here's how #255366 works with other colors. Named schemes with #255366 in its natural role, and a note on why the supporting colors balance it.

Coastal Morning Lead · 5 colors

Lead #255366 Accent #A6C4BF Surface #DEDABF Secondary #9AA0A0 Anchor #1F344A

Dark Slate Gray opens this coastal palette with sea-glass and warm sand alongside it, grounded by driftwood grey and a deep-navy anchor.

Nordic Calm Accent · 5 colors

Accent #255366 Secondary #AEB4B8 Surface #F1F2F0 Support #7B93A6 Anchor #2E3236

Dark Slate Gray keeps this Nordic scheme quiet — cool greys and a soft white around it, a muted-blue support and a charcoal anchor.

Tech Product Signal · 5 colors

Signal #255366 Surface #14161A Highlight #F4F6F8 Secondary #596672 Accent #4C7587

Dark Slate Gray is the vivid signal in this product UI — on a near-black surface with cool white, a slate grey and a lighter tint of Dark Slate Gray.

Vintage Leather Lead · 5 colors

Lead #255366 Secondary #6F5216 Surface #E2DCC0 Accent #385244 Anchor #56233D

Dark Slate Gray plays the worn-leather lead, deepened by saddle brown and an oxblood anchor, softened by aged cream and cooled by a muted forest green.

Minimal Editorial Surface · 5 colors

Surface #F6F4EF Accent #255366 Secondary #68777E Support #969386 Ink #16140F

Dark Slate Gray is the single accent in this high-contrast editorial system — set on near-white paper against near-black ink, with a warm grey and a desaturated tint of Dark Slate Gray carrying the quiet middle.

Build a working theme in the generator →

Color Lab

How #255366 actually behaves in design work — read from its OKLCH lightness, chroma and hue, not just its raw numbers. Ten signals to help you decide where this color earns its place.

Warmth 32/100

Cool

Reads cool and recessive — calming, technical, good for trust-led UI.

Softness 40/100

Moderate

Middle-weight — neither delicate nor heavy.

Depth 56/100

Moderate

Mid depth — usable as an accent or a muted ground.

Naturalness 1/100

Very low

Reads engineered rather than organic — synthetic, digital.

Vintage feel 40/100

Moderate

A faint retro warmth without tipping into sepia.

Luxury 61/100

High

Restrained and premium — deep, quiet, high-end packaging and fashion.

Brand distinctiveness 23/100

Low

Quiet and neutral — a supporting tone, not a signature.

UI accent fit 62/100

High

Strong interactive accent — visible and can carry a legible label.

Surface fit 40/100

Low

Usable as a tinted surface in measured doses.

Print safety 84/100

Very high

Reproduces faithfully in CMYK — safe for packaging and print.

Pairs with #255366

For UI

For branding

For interior

For fashion

People also use #255366 with

Viridian Yale Blue Garnet Platinum Charcoal

UI roles & guardrails

Primary action Safe as a filled button with white label. AAA

Body text Passes on white at 16px and above. Pass

Large display Fine for headings 24px+ on white. Pass

Background Pair with white text at 8.4:1. Use

Subtle surface Use #CDDFE6 for cards and hover fills. Tint 80

Avoid beside #243C65 — the hue gap is too small to read as intentional. Clash

In real applications

Not a swatch to memorise — a color to build with. Here is #255366 at work across the surfaces designers actually ship.

Website / UI

Northwind Sign up

Build faster.

A working theme, generated in seconds.

Dashboard

Revenue

$48.2k ▲ 12%

Brand

AVELINE

Studio

Poster

Nov 14 · 8PM

NIGHT
MARKET

Packaging

BLOOM

Botanical Wash

250 ml

Interior

Every model

Export

:root {
  --color-base: #255366;
  --color-base-rgb: 37 83 102;
  --color-base-oklch: oklch(41.9% 0.059 227.8);
  --color-50: #F3F9FB;
  --color-100: #E0EFF5;
  --color-200: #C3DEE9;
  --color-300: #99C4D6;
  --color-400: #72A9C0;
  --color-500: #518BA4;
  --color-600: #446D7E;
  --color-700: #344F5A;
  --color-800: #25353C;
  --color-900: #182125;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  dark-slate-gray: {
    50: '#F3F9FB',
    100: '#E0EFF5',
    200: '#C3DEE9',
    300: '#99C4D6',
    400: '#72A9C0',
    500: '#518BA4',
    600: '#446D7E',
    700: '#344F5A',
    800: '#25353C',
    900: '#182125',
  },
}

$base: #255366;
$base-ink: #FFFFFF;
$base-50: #F3F9FB;
$base-100: #E0EFF5;
$base-200: #C3DEE9;
$base-300: #99C4D6;
$base-400: #72A9C0;
$base-500: #518BA4;
$base-600: #446D7E;
$base-700: #344F5A;
$base-800: #25353C;
$base-900: #182125;
$base-hover: #1D4151;
$base-subtle: #B3CFDB;

{
    "color": {
        "base": {
            "value": "#255366",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F3F9FB",
                "type": "color"
            },
            "100": {
                "value": "#E0EFF5",
                "type": "color"
            },
            "200": {
                "value": "#C3DEE9",
                "type": "color"
            },
            "300": {
                "value": "#99C4D6",
                "type": "color"
            },
            "400": {
                "value": "#72A9C0",
                "type": "color"
            },
            "500": {
                "value": "#518BA4",
                "type": "color"
            },
            "600": {
                "value": "#446D7E",
                "type": "color"
            },
            "700": {
                "value": "#344F5A",
                "type": "color"
            },
            "800": {
                "value": "#25353C",
                "type": "color"
            },
            "900": {
                "value": "#182125",
                "type": "color"
            }
        }
    }
}

Palettes built on #255366

Color Lab

Pairs with #255366

UI roles & guardrails

In real applications

Scales

Every model

Export