Tailwind CSS v4 default palette
Tailwind slate-400: #90A1B9
In Tailwind CSS v4, slate-400 is defined as --color-slate-400: oklch(70.4% 0.04 256.788), which is #90A1B9 in hex and rgb(144, 161, 185): a light, muted blue. In Tailwind v3, slate-400 was #94A3B8.
In OKLCH, slate-400 has a lightness of 70.4%, chroma 0.040 and hue 256.8°.
The value fits inside sRGB, so the hex #90A1B9 represents it without loss on any screen.
In v3, slate-400 was #94A3B8. The v4 value is ΔE OK 0.8 away, below the point where most people can tell them apart; v4 is darker.
Tailwind slate is the bluest of the gray scales, a cool gray that pairs well with blue and indigo accents.
Color codes for slate-400
| Tailwind v4 token | --color-slate-400 |
|---|---|
| OKLCH (source value) | oklch(70.4% 0.04 256.788) |
| HEX | #90A1B9 |
| RGB | rgb(144, 161, 185) |
| HSL | hsl(215, 23%, 65%) |
| HWB | hwb(215 56% 27%) |
| CMYK (naive, no ICC profile) | cmyk(22%, 13%, 0%, 27%) |
| Decimal | 9,478,585 |
| Tailwind v3 hex | #94A3B8 |
| Utility classes | bg-slate-400, text-slate-400, border-slate-400 |
Tailwind slate scale
Contrast and accessibility
On slate-400, black text has a contrast ratio of 7.98:1 and passes AAA at any text size; white text reaches 2.63:1.
WCAG 2.2 contrast ratios (success criteria 1.4.3 and 1.4.6: AA needs 4.5:1 for normal text and 3:1 for large text, AAA needs 7:1 and 4.5:1). APCA Lc is the lightness contrast from the APCA-W3 0.0.98G model proposed for WCAG 3; a higher absolute value is more readable, and Lc 75 is its suggested minimum for body text.
| Pair | Ratio | AA | AA large | AAA | AAA large | APCA Lc |
|---|---|---|---|---|---|---|
| Black text on slate-400 | 7.98:1 | Pass | Pass | Pass | Pass | 52.7 |
| White text on slate-400 | 2.63:1 | Fail | Fail | Fail | Fail | −56.4 |
| Slate-400 text on white | 2.63:1 | Fail | Fail | Fail | Fail | 51.3 |
| Slate-400 text on black | 7.98:1 | Pass | Pass | Pass | Pass | −50.6 |
Tints and shades
Each step mixes var(--color-slate-400) with white (tints) or black (shades) in gamma-encoded sRGB, the same result as color-mix(in srgb, var(--color-slate-400), white 25%) in CSS.
Tints (mixed with white)
- 5%
#96a6bd - 15%
#a1afc4 - 25%
#acb9cb - 35%
#b7c2d2 - 45%
#c2cbd9 - 55%
#cdd5e0 - 65%
#d8dee7 - 75%
#e3e8ee - 85%
#eef1f5 - 95%
#f9fafc
Shades (mixed with black)
- 5%
#8999b0 - 15%
#7a899d - 25%
#6c798b - 35%
#5e6978 - 45%
#4f5966 - 55%
#414853 - 65%
#323841 - 75%
#24282e - 85%
#16181c - 95%
#070809
Color harmonies
Rotating the hue in OKLCH while keeping lightness and chroma, slate-400's complementary color is #AE9D84 (close to rosybrown), its analogous colors are #86A5B3 and #9D9CB8, and its triadic partners are #B79697 and #94A68D. For text on top, black gives the higher contrast.
| Harmony | Rotation | Color |
|---|---|---|
| Complementary | +180° | #ae9d84 |
| Analogous | −30°, +30° | #86a5b3#9d9cb8 |
| Triadic | +120°, +240° | #b79697#94a68d |
| Split-complementary | +150°, +210° | #b6998b#a2a285 |
Computed in OKLCH: the hue is rotated by 180° (complementary), ±30° (analogous), ±120° (triadic) and 180° ±30° (split-complementary) while lightness and chroma stay fixed. Results that fall outside sRGB are brought back with the CSS Color 4 gamut mapping algorithm. Because this uses OKLCH, the values differ from tools that rotate hue in HSL, but every color keeps the same perceived lightness.
Warm or cool?
Tailwind slate-400 is a cool color: its hue is 215° on the HSL wheel, in the green, blue and violet range that is conventionally called cool.
Nearest named and Tailwind colors
Distance is ΔE OK, the Euclidean distance in OKLab multiplied by 100. Values under about 2 are hard to tell apart side by side.
Code snippets
<div class="bg-slate-400 text-black">...</div>
<p class="text-slate-400 border-slate-400">...</p>.element {
color: var(--color-slate-400);
background-color: oklch(70.4% 0.04 256.788);
border-color: #90a1b9;
outline-color: rgb(144 161 185);
}import SwiftUI
extension Color {
static let slate400 = Color(red: 0.565, green: 0.631, blue: 0.725)
}import androidx.compose.ui.graphics.Color
val Slate400 = Color(0xFF90A1B9)import 'package:flutter/material.dart';
const slate400 = Color(0xFF90A1B9);<!-- res/values/colors.xml -->
<color name="slate_400">#90A1B9</color>Frequently asked questions
- What is the hex code for Tailwind slate-400?
- In Tailwind CSS v4, slate-400 is oklch(70.4% 0.04 256.788), which converts to #90A1B9 (rgb(144, 161, 185)) in sRGB. In Tailwind v3 the same name was #94A3B8.
- What is the difference between slate-400 in Tailwind v3 and v4?
- v3 used the hex #94A3B8; v4 redefined the palette in OKLCH as oklch(70.4% 0.04 256.788). In v3, slate-400 was #94A3B8. The v4 value is ΔE OK 0.8 away, below the point where most people can tell them apart; v4 is darker.
- How do I use slate-400 in plain CSS?
- Tailwind v4 defines every palette color as a theme variable, so in CSS you write var(--color-slate-400). By default Tailwind only emits the variables your project uses; @theme static emits all of them.
- Can you use white text on slate-400?
- White text on slate-400 has a contrast ratio of 2.63:1, which fails AA even for large text under WCAG 2.2. Black text reaches 7.98:1 and passes both AA and AAA. In APCA terms that is Lc −56.4 for white and Lc 52.7 for black.
- Which CSS named color is closest to slate-400?
- The closest is darkgray (#A9A9A9) at ΔE OK 5.0, followed by cadetblue and rosybrown.
Last reviewed by Arielton Oberek.