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bg-blue-900

Tailwind Blue 900

#1E3A8A·Blue family·Shade 900

Color Values

HEX
#1E3A8A
RGB
rgb(30, 58, 138)
HSL
hsl(224, 64%, 33%)
OKLCH
oklch(0.379 0.138 266)
CMYK
cmyk(78%, 58%, 0%, 46%)
CSS Variable
var(--color-blue-900)
Tailwind Class
bg-blue-900

Accessibility Score

60/100

Good

Based on WCAG 2.1 contrast ratios against white and black backgrounds.

On White

10.36:1

AAA

On Black

2.03:1

Fail
Test in Contrast Checker →

Tailwind Usage — All Utilities

Background

bg-blue-900

Text

text-blue-900

Border

border-blue-900

Ring

ring-blue-900

Outline

outline-blue-900

Fill

fill-blue-900

Stroke

stroke-blue-900

From (gradient)

from-blue-900

Via (gradient)

via-blue-900

To (gradient)

to-blue-900

Placeholder

placeholder-blue-900

Caret

caret-blue-900

Accent

accent-blue-900

Decoration

decoration-blue-900

Shadow Color

shadow-blue-900

Tailwind v3 Config (extend custom color)

// tailwind.config.js module.exports = { theme: { extend: { colors: { 'blue-900': '#1e3a8a', }, }, }, };

CSS Equivalent

/* Hex */
background-color: #1E3A8A;

/* RGB */
background-color: rgb(30, 58, 138);

/* HSL */
background-color: hsl(224, 64%, 33%);

/* OKLCH (CSS Color Level 4) */
background-color: oklch(0.379 0.138 266);

/* CSS Custom Property (Tailwind v4) */
background-color: var(--color-blue-900);

/* Gradient example */
background: linear-gradient(135deg, #eff6ff 0%, #172554 100%);

OKLCH — Modern Color Space

Lightness (L)

0.379

38% perceived brightness

Chroma (C)

0.138

Color intensity / saturation

Hue (H)

266°

Angle on perceptual hue wheel

oklch(0.379 0.138 266)

OKLCH is a perceptually uniform color space in CSS Color Level 4. Unlike HSL, equal steps in L produce equal perceived lightness changes — making it ideal for building accessible, harmonious design system scales.

Design Recommendations

Strong dark tone

Shade 900 of the Blue palette

Recommended Uses

  • ✓Body text on white
  • ✓Dark panel backgrounds
  • ✓Near-dark UI elements
  • ✓Footer backgrounds
  • ✓High-contrast headings

Avoid

✗On dark backgrounds — contrast will be insufficient.

Preview

On White

Aa Bb Cc

On Black

Aa Bb Cc

As Background

Aa Bb Cc — #1E3A8A

Blue Shades

50

100

200

300

400

500

600

700

800

900

950

Similar Tailwind Colors

Perceptually close shades from other Tailwind color families.

Tailwind Indigo 900

#312E81

Tailwind Indigo 800

#3730A3

Tailwind Sky 900

#0C4A6E

Tailwind Cyan 900

#164E63

Tailwind Slate 700

#334155

Tailwind Gray 700

#374151

Nearest Named Color

Tailwind Blue 900

Nearest Tailwind equivalent — #1E3A8A

Design & Accessibility Guides

Guide

Building an Accessible Color System

Design Systems · 10 min read

Guide

WCAG Contrast Ratios Explained

WCAG · 8 min read

Guide

WCAG AA vs AAA: Which Standard Should You Target?

WCAG · 7 min read

Frequently Asked Questions

What is the hex code for Tailwind Blue 900?
Tailwind Blue 900 has the hex code #1E3A8A. Its RGB value is rgb(30, 58, 138) and its HSL value is hsl(224, 64%, 33%).
What Tailwind utility classes use Blue 900?
Use bg-blue-900 for backgrounds, text-blue-900 for text color, border-blue-900 for borders, and ring-blue-900 for focus rings. In Tailwind v4 the CSS variable var(--color-blue-900) is available natively.
Is Tailwind Blue 900 WCAG accessible?
Tailwind Blue 900 achieves a 10.36:1 contrast ratio on white (AAA) and 2.03:1 on black (Fail). Its overall accessibility score is 60/100 (Good).
What is the OKLCH value for Tailwind Blue 900?
Tailwind Blue 900 in OKLCH is oklch(0.379 0.138 266) — lightness 0.379, chroma 0.138, hue 266°. OKLCH is a perceptually uniform space supported natively in modern CSS via the `color()` function.
What is Tailwind Blue 900 used for?
At shade 900, Tailwind Blue 900 is best described as "Strong dark tone". Recommended uses: Body text on white, Dark panel backgrounds, Near-dark UI elements.
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