What color is #3902BB?

#3902BB is a dark, vivid indigo. In RGB it is rgb(57, 2, 187), and in HSL hsl(258, 98%, 37%).

Is #3902BB accessible as text?

On white, #3902BB has a contrast ratio of 11.05:1 (passes WCAG AA for body text); on black it is 1.90:1 (fails). For text placed on #3902BB, use white for the best readability.

What is the closest Tailwind color to #3902BB?

The nearest Tailwind CSS token is indigo-800 (#372AAC).

What colors go well with #3902BB?

#3902BB pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #83BB02. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #3902BB below.

Is #3902BB good for buttons?

#3902BB works well for buttons and highlights, but use white text on #3902BB — black text only reaches 1.90:1, below the 4.5:1 needed for normal-size labels.

Is #3902BB the same as CSS mediumblue?

No — #3902BB is not the CSS named color mediumblue, but mediumblue (#0000CD) is the closest CSS named color by perceptual color distance — it sits in a different color family, so treat it as a rough reference, not a match.

#3902BB Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #3902BB

Not just a swatch — here's how #3902BB works with other colors. Named schemes with #3902BB in its natural role, and a note on why the supporting colors balance it.

Tech Product Signal · 5 colors

Signal #3902BB Surface #14161A Highlight #F4F6F8 Secondary #5B6672 Accent #5249D8

Klein 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 Klein Blue.

Berry & Cream Lead · 5 colors

Lead #3902BB Surface #F6E5D8 Anchor #5B2142 Accent #E5C2C9 Secondary #322B2F

Klein Blue 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 #3902BB Secondary #606599 Support #9D9088 Ink #18140F

Klein 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 Klein Blue carrying the quiet middle.

Coastal Morning Lead · 5 colors

Lead #3902BB Accent #A5C4C2 Surface #EAD5BF Secondary #9AA0A1 Anchor #22344A

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

Sunset Warmth Glow · 5 colors

Glow #3902BB Secondary #E86A71 Accent #F6934E Anchor #583B57 Surface #F7E7D7

Klein Blue 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 #3902BB 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 17/100

Cool

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

Softness 22/100

Low

Firm and assertive — carries weight and contrast.

Depth 67/100

High

Deep and grounding — anchors a layout, strong dark-mode base.

Naturalness 0/100

Very low

Reads engineered rather than organic — synthetic, digital.

Vintage feel 11/100

Very low

Clean and current — no dusty, aged cast.

Luxury 57/100

Moderate

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

Brand distinctiveness 90/100

Very high

Bold and ownable — memorable as a primary brand color.

UI accent fit 49/100

Moderate

Workable accent with care around contrast.

Surface fit 15/100

Very low

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

Print safety 64/100

High

Prints close, with a slight loss of vibrancy.

Pairs with #3902BB

For UI

For branding

For interior

For fashion

People also use #3902BB with

Neon Blue Dark Orchid Greenery Gainsboro Russian Violet

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 11.1:1. Use

Subtle surface Use #D6C8F6 for cards and hover fills. Tint 80

Avoid beside #7702BB — 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 #3902BB 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: #3902BB;
  --color-base-rgb: 57 2 187;
  --color-base-oklch: oklch(38.6% 0.234 278.7);
  --color-50: #F5F0FE;
  --color-100: #E3D8FD;
  --color-200: #C7B1FC;
  --color-300: #9E78F7;
  --color-400: #7948EA;
  --color-500: #5824D1;
  --color-600: #49249E;
  --color-700: #38206F;
  --color-800: #271948;
  --color-900: #19112C;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  klein-blue: {
    50: '#F5F0FE',
    100: '#E3D8FD',
    200: '#C7B1FC',
    300: '#9E78F7',
    400: '#7948EA',
    500: '#5824D1',
    600: '#49249E',
    700: '#38206F',
    800: '#271948',
    900: '#19112C',
  },
}

$base: #3902BB;
$base-ink: #FFFFFF;
$base-50: #F5F0FE;
$base-100: #E3D8FD;
$base-200: #C7B1FC;
$base-300: #9E78F7;
$base-400: #7948EA;
$base-500: #5824D1;
$base-600: #49249E;
$base-700: #38206F;
$base-800: #271948;
$base-900: #19112C;
$base-hover: #2E0295;
$base-subtle: #C0ABF3;

{
    "color": {
        "base": {
            "value": "#3902BB",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F5F0FE",
                "type": "color"
            },
            "100": {
                "value": "#E3D8FD",
                "type": "color"
            },
            "200": {
                "value": "#C7B1FC",
                "type": "color"
            },
            "300": {
                "value": "#9E78F7",
                "type": "color"
            },
            "400": {
                "value": "#7948EA",
                "type": "color"
            },
            "500": {
                "value": "#5824D1",
                "type": "color"
            },
            "600": {
                "value": "#49249E",
                "type": "color"
            },
            "700": {
                "value": "#38206F",
                "type": "color"
            },
            "800": {
                "value": "#271948",
                "type": "color"
            },
            "900": {
                "value": "#19112C",
                "type": "color"
            }
        }
    }
}

Palettes built on #3902BB

Color Lab

Pairs with #3902BB

UI roles & guardrails

In real applications

Scales

Every model

Export