What color is #3540BB?

#3540BB is a medium blue. In RGB it is rgb(53, 64, 187), and in HSL hsl(235, 56%, 47%).

Is #3540BB accessible as text?

On white, #3540BB has a contrast ratio of 8.07:1 (passes WCAG AA for body text); on black it is 2.60:1 (fails). For text placed on #3540BB, use white for the best readability.

What is the closest Tailwind color to #3540BB?

The nearest Tailwind CSS token is blue-800 (#193CB8).

What colors go well with #3540BB?

#3540BB pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #BBB035. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #3540BB below.

Is #3540BB good for buttons?

#3540BB works well for buttons and highlights, but use white text on #3540BB — black text only reaches 2.60:1, below the 4.5:1 needed for normal-size labels.

Is #3540BB the same as CSS darkslateblue?

No — #3540BB is not the CSS named color darkslateblue, but darkslateblue (#483D8B) is the closest CSS named color.

#3540BB Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #3540BB

Not just a swatch — here's how #3540BB works with other colors. Named schemes with #3540BB in its natural role, and a note on why the supporting colors balance it.

Tech Product Signal · 5 colors

Signal #3540BB Surface #14161A Highlight #F4F6F8 Secondary #5B6672 Accent #556AD9

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

Coastal Morning Lead · 5 colors

Lead #3540BB Accent #A5C4C2 Surface #EAD5C0 Secondary #9AA0A1 Anchor #21344A

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

Berry & Cream Lead · 5 colors

Lead #3540BB Surface #F6E5D8 Anchor #5B2143 Accent #E5C2C9 Secondary #322B2F

Cerulean sits between cream and a deep berry here, softened by a blush accent and grounded by charcoal.

Minimal Editorial Surface · 5 colors

Surface #F8F4EF Accent #3540BB Secondary #6E7AA4 Support #9D8F88 Ink #18140F

Cerulean 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 Cerulean carrying the quiet middle.

Sunset Warmth Glow · 5 colors

Glow #3540BB Secondary #E86A73 Accent #F6924F Anchor #573B58 Surface #F7E7D7

Cerulean glows at the center of this sunset palette, joined by coral and gold, deepened by a plum anchor and cooled with cream.

Build a working theme in the generator →

Color Lab

How #3540BB 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 13/100

Cool

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

Softness 30/100

Low

Firm and assertive — carries weight and contrast.

Depth 59/100

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 25/100

Low

Clean and current — no dusty, aged cast.

Luxury 56/100

Moderate

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

Brand distinctiveness 74/100

High

Bold and ownable — memorable as a primary brand color.

UI accent fit 80/100

Very high

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

Surface fit 11/100

Very low

Too saturated or mid-toned for big areas — keep it to accents.

Print safety 68/100

High

Prints close, with a slight loss of vibrancy.

Pairs with #3540BB

For UI

For branding

For interior

For fashion

People also use #3540BB with

Carolina Blue Grape Brass Gainsboro Prussian Blue

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 8.1:1. Use

Subtle surface Use #D9DBEF for cards and hover fills. Tint 80

Avoid beside #5635BB — 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 #3540BB at work across the surfaces designers actually ship.

Website / UI

Northwind Sign up

Build faster.

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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: #3540BB;
  --color-base-rgb: 53 64 187;
  --color-base-oklch: oklch(44.6% 0.191 272.0);
  --color-50: #F3F3FC;
  --color-100: #DFE1F7;
  --color-200: #BFC3ED;
  --color-300: #9399DC;
  --color-400: #6B72C7;
  --color-500: #4951AC;
  --color-600: #3E4484;
  --color-700: #31355E;
  --color-800: #23253E;
  --color-900: #171826;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  cerulean: {
    50: '#F3F3FC',
    100: '#DFE1F7',
    200: '#BFC3ED',
    300: '#9399DC',
    400: '#6B72C7',
    500: '#4951AC',
    600: '#3E4484',
    700: '#31355E',
    800: '#23253E',
    900: '#171826',
  },
}

$base: #3540BB;
$base-ink: #FFFFFF;
$base-50: #F3F3FC;
$base-100: #DFE1F7;
$base-200: #BFC3ED;
$base-300: #9399DC;
$base-400: #6B72C7;
$base-500: #4951AC;
$base-600: #3E4484;
$base-700: #31355E;
$base-800: #23253E;
$base-900: #171826;
$base-hover: #2A3396;
$base-subtle: #C5C8E8;

{
    "color": {
        "base": {
            "value": "#3540BB",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F3F3FC",
                "type": "color"
            },
            "100": {
                "value": "#DFE1F7",
                "type": "color"
            },
            "200": {
                "value": "#BFC3ED",
                "type": "color"
            },
            "300": {
                "value": "#9399DC",
                "type": "color"
            },
            "400": {
                "value": "#6B72C7",
                "type": "color"
            },
            "500": {
                "value": "#4951AC",
                "type": "color"
            },
            "600": {
                "value": "#3E4484",
                "type": "color"
            },
            "700": {
                "value": "#31355E",
                "type": "color"
            },
            "800": {
                "value": "#23253E",
                "type": "color"
            },
            "900": {
                "value": "#171826",
                "type": "color"
            }
        }
    }
}