Conversions, palettes, contrast & design ideas for this color.
Color profile
#0D231E is a cool color from the Teal family, closest in name to “Nightmare”. In RGB it is rgb(13, 35, 30); in HSL, hsl(166, 46%, 9%).
The color Nightmare, with hexadecimal code #0d231e, is categorized under the cyan family—a cool, refreshing hue fundamental to CMYK printing. Cyan evokes clarity, focus, and digital innovation, appearing across tech interfaces and futuristic design systems. Additionally, it evokes emotions such as Power, Elegance, Formality, Mystery and Authority. Cyan or blue-green is associated with healing, water, and tranquility. It can symbolize communication and clarity in various cultures. With a moderate saturation of 46%, it has a softened, muted quality that lends sophistication and works well for backgrounds and secondary elements. At only 9% lightness, this extremely dark shade approaches black, delivering maximum drama and contrast when paired with lighter elements. This color is ideal for designs that aim to express Power, Elegance, Formality, Mystery, or Authority. It can be effectively used in web design, branding, and marketing materials to attract attention and convey specific messages.
Key facts
The story of this color
Nightmare (#0D231E) belongs to the Teal color family.
This deep, saturated shade conveys authority and richness. Deep tones are favored in luxury packaging, evening-event branding, and dark-mode interfaces where they provide dramatic contrast against lighter elements.
Teal—named after the Eurasian teal duck's distinctive head stripe—gained prominence as a design color in the 1990s. However, teal pigments trace back to ancient Egyptian faience, a ceramic technique that produced striking blue-green glazes for amulets and tiles. In contemporary culture, teal ribbons symbolize ovarian cancer awareness and anxiety-disorder advocacy.
Teal bridges the reliability of blue with the renewal of green, making it versatile across healthcare, education, and technology sectors. Pair teal with coral or warm peach for a modern complementary scheme, or with light gray for a clean, professional interface. Teal works well as both a primary and accent color.
Sitting on the cool side of the spectrum (hue 166°), it promotes a feeling of calm distance and intellectual clarity, which is why cool hues dominate corporate identities, healthcare design, and productivity tools. At 46% saturation, the color has a muted, sophisticated quality that pairs well with bolder accents. It works as a background, a border, or a secondary element in layered compositions.
Teal evokes calm confidence, open communication, and clarity of thought. It feels more energetic than navy but more grounded than bright cyan. In branding, teal signals trustworthiness with a creative edge—bridging corporate reliability and startup innovation.
At just 9% lightness, this is an extremely dark shade that approaches black. It is best reserved for text, thin borders, or dramatic full-bleed backgrounds paired with light typography.
Use teal as a hero-section background color paired with white text and photography for a healthcare or wellness brand. Create duotone imagery (teal + coral) for vibrant social media graphics. In dashboards, teal chart lines stand out clearly against white backgrounds.
Every format
Every way to write Nightmare — one-tap copy on every format; tap on any card to learn what it is and when to use it.
#0D231E
Hexadecimal is the web’s universal color notation — two digits each for red, green and blue. Drop it straight into HTML, CSS or any design tool.
rgb(13, 35, 30)
RGB is the additive Red-Green-Blue model every screen uses to emit light. The default choice for websites, apps and on-screen UI.
hsl(166, 46%, 9%)
HSL breaks a color into Hue, Saturation and Lightness — the most intuitive way to lighten, darken or mute a color in CSS.
hsv(166, 63%, 14%)
HSV (also called HSB) maps Hue, Saturation and Value/Brightness. It is the model behind the color pickers in Photoshop, Figma and most design apps.
hwb(166 5% 86%)
HWB blends a pure hue with Whiteness and Blackness — a painter-friendly model added in CSS Color 4 for quick tints and shades.
cmyk(63%, 0%, 14%, 86%)
CMYK is the subtractive Cyan-Magenta-Yellow-Black ink model. Use these values when preparing artwork for a printer or commercial press.
oklch(23.62% 0.030 176.90)
OKLCH is a modern, perceptually-uniform space (Lightness, Chroma, Hue). It powers smooth gradients and accessible palettes in today’s CSS.
oklab(23.62% -0.030 0.002)
OKLab is the Cartesian form of OKLCH — ideal for blending and interpolating colors without the muddy midpoints older spaces produce.
L: 11.83, a: -10.36, b: 0.67
CIELAB is a device-independent, perceptually-uniform space. It is the standard for measuring color difference (ΔE) and matching across devices.
L: 11.83, C: 10.38, H: 176.31
LCH is CIELAB in cylindrical form — Lightness, Chroma and Hue — letting you adjust vividness and hue while staying perceptually even.
X: 1.00, Y: 1.38, Z: 1.44
CIE XYZ is the 1931 master space that underpins every other model here — the scientific bridge used to convert between color systems.
860958
The 24-bit integer value of the color — handy for databases, APIs, game engines and low-level graphics code.
Channel breakdown
How much red, green and blue light mixes into Nightmare.
Percentages show each channel's share of the total light (R + G + B) in Nightmare.
Ink coverage
Ink needed to reproduce Nightmare in four-color print. Heaviest ink: Key (Black).
Print tip: treat these values as a starting point — final output depends on printer profile, paper stock and calibration.
Accessibility · WCAG
How bright Nightmare is, and how far black and white text clear each WCAG bar.
Contrast ratio · 1:1 → 21:1 (log scale)
Developer shortcuts
Copy-and-paste CSS for Nightmare — per-line copy, or grab the whole block.
background-color: #0D231E;
color: #0D231E;
border: 2px solid #0D231E;
background-color: rgb(13, 35, 30);
background-color: hsl(166, 46%, 9%);
--color: #0D231E;
Shades · light to dark
Lighter and darker steps of Nightmare — the color's full brightness range in one strip.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Harmony · 180° apart
Two colors opposite on the wheel — maximum contrast for attention-grabbing accents.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Harmony · adjacent hues
Neighboring hues on the wheel — harmonious, calm combinations that feel unified.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Harmony · 120° apart
Three colors evenly spaced on the wheel — vibrant and energetic, yet balanced.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Harmony · 90° apart
Four colors evenly spaced on the wheel (tetradic) — rich schemes with multiple accents.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Accessibility
How Nightmare reads across five kinds of color vision — a ✓ Friendly verdict means the color difference stays distinguishable for that vision type.
The dot marks the original color. Hover any shade to copy its hex.
Harmony overview
The lead color from each harmony scheme, side by side — a shortcut to the full palettes above.
Perceptually nearby
A step away in brightness, richness or shade — each still feels like the same color.
From the color-name library
The closest named colors to #0D231E — same mood, each with its own character.
Looking for more Cyan shades? Browse Cyan colors →
Inspiration
Curated Unsplash photos that carry the mood of Nightmare — hover any tile to download it or view the original.
Good to know
Harmony