What color is #045378?

#045378 is a dark, vivid cyan-blue. In RGB it is rgb(4, 83, 120), and in HSL hsl(199, 94%, 24%).

Is #045378 accessible as text?

On white, #045378 has a contrast ratio of 8.35:1 (passes WCAG AA for body text); on black it is 2.51:1 (fails). For text placed on #045378, use white for the best readability.

What is the closest Tailwind color to #045378?

The nearest Tailwind CSS token is sky-900 (#024A70).

What colors go well with #045378?

#045378 pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #772804. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #045378 below.

Is #045378 good for buttons?

#045378 works well for buttons and highlights, but use white text on #045378 — black text only reaches 2.51:1, below the 4.5:1 needed for normal-size labels.

Is #045378 the same as CSS darkslategray?

No — #045378 is not the CSS named color darkslategray, but darkslategray (#2F4F4F) is the closest CSS named color.

#045378 Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #045378

Not just a swatch — here's how #045378 works with other colors. Named schemes with #045378 in its natural role, and a note on why the supporting colors balance it.

Coastal Morning Lead · 5 colors

Lead #045378 Accent #A6C4C0 Surface #DEDABF Secondary #9AA0A0 Anchor #1F344A

Classic Blue 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 #045378 Secondary #AEB4B8 Surface #F1F2F0 Support #7C93A6 Anchor #2E3236

Classic Blue 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 #045378 Surface #14161A Highlight #F4F6F8 Secondary #5A6672 Accent #3C7598

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

Vintage Leather Lead · 5 colors

Lead #045378 Secondary #7F4439 Surface #E2DDC0 Accent #385245 Anchor #57233C

Classic Blue 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 #045378 Secondary #637885 Support #969386 Ink #16140F

Classic Blue 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 Classic Blue carrying the quiet middle.

Build a working theme in the generator →

Color Lab

How #045378 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 23/100

Cool

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

Softness 37/100

Low

Middle-weight — neither delicate nor heavy.

Depth 57/100

Moderate

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

Naturalness 0/100

Very low

Reads engineered rather than organic — synthetic, digital.

Vintage feel 48/100

Moderate

A faint retro warmth without tipping into sepia.

Luxury 63/100

High

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

Brand distinctiveness 24/100

Low

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

UI accent fit 73/100

High

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

Surface fit 30/100

Low

Usable as a tinted surface in measured doses.

Print safety 78/100

High

Reproduces faithfully in CMYK — safe for packaging and print.

Pairs with #045378

For UI

For branding

For interior

For fashion

People also use #045378 with

Shamrock Green Navy 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 #BEE2F2 for cards and hover fills. Tint 80

Avoid beside #042C77 — 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 #045378 at work across the surfaces designers actually ship.

Website / UI

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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: #045378;
  --color-base-rgb: 4 83 120;
  --color-base-oklch: oklch(42.0% 0.091 237.5);
  --color-50: #F0FAFE;
  --color-100: #D8F1FD;
  --color-200: #B1E4FC;
  --color-300: #7BCEF4;
  --color-400: #4BB6E7;
  --color-500: #2899CD;
  --color-600: #26769B;
  --color-700: #21556D;
  --color-800: #1A3947;
  --color-900: #12232B;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  classic-blue: {
    50: '#F0FAFE',
    100: '#D8F1FD',
    200: '#B1E4FC',
    300: '#7BCEF4',
    400: '#4BB6E7',
    500: '#2899CD',
    600: '#26769B',
    700: '#21556D',
    800: '#1A3947',
    900: '#12232B',
  },
}

$base: #045378;
$base-ink: #FFFFFF;
$base-50: #F0FAFE;
$base-100: #D8F1FD;
$base-200: #B1E4FC;
$base-300: #7BCEF4;
$base-400: #4BB6E7;
$base-500: #2899CD;
$base-600: #26769B;
$base-700: #21556D;
$base-800: #1A3947;
$base-900: #12232B;
$base-hover: #03425F;
$base-subtle: #9BD4EE;

{
    "color": {
        "base": {
            "value": "#045378",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F0FAFE",
                "type": "color"
            },
            "100": {
                "value": "#D8F1FD",
                "type": "color"
            },
            "200": {
                "value": "#B1E4FC",
                "type": "color"
            },
            "300": {
                "value": "#7BCEF4",
                "type": "color"
            },
            "400": {
                "value": "#4BB6E7",
                "type": "color"
            },
            "500": {
                "value": "#2899CD",
                "type": "color"
            },
            "600": {
                "value": "#26769B",
                "type": "color"
            },
            "700": {
                "value": "#21556D",
                "type": "color"
            },
            "800": {
                "value": "#1A3947",
                "type": "color"
            },
            "900": {
                "value": "#12232B",
                "type": "color"
            }
        }
    }
}

Palettes built on #045378

Color Lab

Pairs with #045378

UI roles & guardrails

In real applications

Scales

Every model

Export