What color is #3F447E?

#3F447E is a dark, muted blue-violet. In RGB it is rgb(63, 68, 126), and in HSL hsl(235, 33%, 37%).

Is #3F447E accessible as text?

On white, #3F447E has a contrast ratio of 8.98:1 (passes WCAG AA for body text); on black it is 2.34:1 (fails). For text placed on #3F447E, use white for the best readability.

What is the closest Tailwind color to #3F447E?

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

What colors go well with #3F447E?

#3F447E pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #7D783F. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #3F447E below.

Is #3F447E good for buttons?

#3F447E works well for buttons and highlights, but use white text on #3F447E — black text only reaches 2.34:1, below the 4.5:1 needed for normal-size labels.

Is #3F447E the same as CSS darkslateblue?

No — #3F447E is not the CSS named color darkslateblue, but darkslateblue (#483D8B) is the closest CSS named color.

#3F447E Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #3F447E

Not just a swatch — here's how #3F447E works with other colors. Named schemes with #3F447E in its natural role, and a note on why the supporting colors balance it.

Coastal Morning Lead · 5 colors

Lead #3F447E Accent #A5C4C2 Surface #EAD5BF Secondary #9AA0A1 Anchor #22344A

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

Vintage Leather Lead · 5 colors

Lead #3F447E Secondary #7F4534 Surface #EED7C2 Accent #365247 Anchor #582239

Dark Slate 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.

Modern Café Dominant · 5 colors

Dominant #3F447E Anchor #3B2923 Surface #F3E1D2 Accent #769F7B Secondary #3C3734

Dark Slate Blue anchors this café scheme as the warm mid-tone, lifted by latte cream and a muted sage accent and grounded by espresso brown and a warm charcoal.

Berry & Cream Lead · 5 colors

Lead #3F447E Surface #F6E5D8 Anchor #5B2142 Accent #E5C2C9 Secondary #322B2F

Dark Slate 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 #3F447E Secondary #6D7186 Support #9D9088 Ink #18140F

Dark Slate 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 Dark Slate Blue carrying the quiet middle.

Build a working theme in the generator →

Color Lab

How #3F447E 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 31/100

Cool

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

Softness 36/100

Low

Middle-weight — neither delicate nor heavy.

Depth 58/100

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 51/100

Moderate

A faint retro warmth without tipping into sepia.

Luxury 64/100

High

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

Brand distinctiveness 26/100

Low

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

UI accent fit 72/100

High

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

Surface fit 29/100

Low

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

Print safety 85/100

Very high

Reproduces faithfully in CMYK — safe for packaging and print.

Pairs with #3F447E

For UI

For branding

For interior

For fashion

People also use #3F447E with

Steel Blue Ultra Violet Olive Brown 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 9.0:1. Use

Subtle surface Use #D7D9E7 for cards and hover fills. Tint 80

Avoid beside #4F3F7D — 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 #3F447E 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: #3F447E;
  --color-base-rgb: 63 68 126;
  --color-base-oklch: oklch(41.2% 0.096 277.6);
  --color-50: #F5F5FA;
  --color-100: #E3E5F2;
  --color-200: #C9CBE4;
  --color-300: #A2A6CD;
  --color-400: #7E82B4;
  --color-500: #5D6297;
  --color-600: #4C5075;
  --color-700: #3A3C55;
  --color-800: #292A38;
  --color-900: #1A1B23;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  dark-slate-blue: {
    50: '#F5F5FA',
    100: '#E3E5F2',
    200: '#C9CBE4',
    300: '#A2A6CD',
    400: '#7E82B4',
    500: '#5D6297',
    600: '#4C5075',
    700: '#3A3C55',
    800: '#292A38',
    900: '#1A1B23',
  },
}

$base: #3F447E;
$base-ink: #FFFFFF;
$base-50: #F5F5FA;
$base-100: #E3E5F2;
$base-200: #C9CBE4;
$base-300: #A2A6CD;
$base-400: #7E82B4;
$base-500: #5D6297;
$base-600: #4C5075;
$base-700: #3A3C55;
$base-800: #292A38;
$base-900: #1A1B23;
$base-hover: #333764;
$base-subtle: #C3C5DB;

{
    "color": {
        "base": {
            "value": "#3F447E",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F5F5FA",
                "type": "color"
            },
            "100": {
                "value": "#E3E5F2",
                "type": "color"
            },
            "200": {
                "value": "#C9CBE4",
                "type": "color"
            },
            "300": {
                "value": "#A2A6CD",
                "type": "color"
            },
            "400": {
                "value": "#7E82B4",
                "type": "color"
            },
            "500": {
                "value": "#5D6297",
                "type": "color"
            },
            "600": {
                "value": "#4C5075",
                "type": "color"
            },
            "700": {
                "value": "#3A3C55",
                "type": "color"
            },
            "800": {
                "value": "#292A38",
                "type": "color"
            },
            "900": {
                "value": "#1A1B23",
                "type": "color"
            }
        }
    }
}