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bg-slate-900

Tailwind Slate 900

#0F172A·Slate family·Shade 900

Color Values

HEX
#0F172A
RGB
rgb(15, 23, 42)
HSL
hsl(222, 47%, 11%)
OKLCH
oklch(0.208 0.040 266)
CMYK
cmyk(64%, 45%, 0%, 84%)
CSS Variable
var(--color-slate-900)
Tailwind Class
bg-slate-900

Accessibility Score

60/100

Good

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

On White

17.85:1

AAA

On Black

1.18:1

Fail
Test in Contrast Checker →

Tailwind Usage — All Utilities

Background

bg-slate-900

Text

text-slate-900

Border

border-slate-900

Ring

ring-slate-900

Outline

outline-slate-900

Fill

fill-slate-900

Stroke

stroke-slate-900

From (gradient)

from-slate-900

Via (gradient)

via-slate-900

To (gradient)

to-slate-900

Placeholder

placeholder-slate-900

Caret

caret-slate-900

Accent

accent-slate-900

Decoration

decoration-slate-900

Shadow Color

shadow-slate-900

Tailwind v3 Config (extend custom color)

// tailwind.config.js module.exports = { theme: { extend: { colors: { 'slate-900': '#0f172a', }, }, }, };

CSS Equivalent

/* Hex */
background-color: #0F172A;

/* RGB */
background-color: rgb(15, 23, 42);

/* HSL */
background-color: hsl(222, 47%, 11%);

/* OKLCH (CSS Color Level 4) */
background-color: oklch(0.208 0.040 266);

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

/* Gradient example */
background: linear-gradient(135deg, #f8fafc 0%, #020617 100%);

OKLCH — Modern Color Space

Lightness (L)

0.208

21% perceived brightness

Chroma (C)

0.040

Color intensity / saturation

Hue (H)

266°

Angle on perceptual hue wheel

oklch(0.208 0.040 266)

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 Slate 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 — #0F172A

Slate Shades

50

100

200

300

400

500

600

700

800

900

950

Similar Tailwind Colors

Perceptually close shades from other Tailwind color families.

Tailwind Gray 900

#111827

Tailwind Zinc 900

#18181B

Tailwind Neutral 900

#171717

Tailwind Stone 900

#1C1917

Tailwind Indigo 950

#1E1B4B

Tailwind Neutral 950

#0A0A0A

Nearest Named Color

Tailwind Slate 900

Nearest Tailwind equivalent — #0F172A

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 Slate 900?
Tailwind Slate 900 has the hex code #0F172A. Its RGB value is rgb(15, 23, 42) and its HSL value is hsl(222, 47%, 11%).
What Tailwind utility classes use Slate 900?
Use bg-slate-900 for backgrounds, text-slate-900 for text color, border-slate-900 for borders, and ring-slate-900 for focus rings. In Tailwind v4 the CSS variable var(--color-slate-900) is available natively.
Is Tailwind Slate 900 WCAG accessible?
Tailwind Slate 900 achieves a 17.85:1 contrast ratio on white (AAA) and 1.18:1 on black (Fail). Its overall accessibility score is 60/100 (Good).
What is the OKLCH value for Tailwind Slate 900?
Tailwind Slate 900 in OKLCH is oklch(0.208 0.040 266) — lightness 0.208, chroma 0.040, hue 266°. OKLCH is a perceptually uniform space supported natively in modern CSS via the `color()` function.
What is Tailwind Slate 900 used for?
At shade 900, Tailwind Slate 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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