Flat Nereid Moss
Flat Nereid Moss (#155F3F) is a deep teal with a jewel character. It carries the deep, saturated richness of a gemstone. Authoritative and slightly formal, it works well for type and heavy UI elements. Its HSL profile (154°, 64%, 23%) places it in the balanced band at a dark lightness. It works well as a headline, icon, or deep background in an otherwise light layout, pairing cleanly with cream, bone, and warm neutrals. For a confident two-color system, pair it with its complementary magenta. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Old Norse flatr, flat / level. As a color modifier, flat implies a clear-and-evenly-spread quality where the hue carries the matte-finish visual register of unmodulated single-plane surface. Sits at the crisp-and-balanced end of the grid, parallel to level and even in usage.
Greek Νηρηΐς, sea-nymph-daughter-of-Nereus. As a color modifier, nereid implies a sea-nymph-and-Aegean-foam quality, the visual register of Hellenic-Nereid-and-Aegean-sea-nymph hand-sea-nymph-and-Aegean-foam Hellenic-Nereid-and-Aegean-sea-nymph-and-Poseidon-court nereid-and-sea-nymph-and-Aegean-foam surfaces under Hellenic-Nereid-and-Aegean-sea-nymph-and-Poseidon-court Aegean-island-and-rocky-cove sea-nymph-light. Sits at the modifier-and-myth end of the grid, parallel to nymph and dryad in usage.
Bryophyta — the nonvascular plants that colonized land 470 million years ago, before vascular plants and far before flowers. The color refers to a thick mat of Hypnum or sphagnum on a temperate forest floor: a soft, slightly yellow-shifted green with the velvet texture of millimeter-scale leaves. Dustier than fern, deeper than lichen, with the slow patience of a plant that lives by absorbing rain through its surface.
Closest matches
The nearest named color in three reference sources, ranked by perceptual distance (ΔE76 in CIELAB). ΔE < 1 is imperceptible to most viewers; ΔE > 10 is clearly different. When two sources point to the same hex they’re merged into one tile; click any to open that color’s page.
Variations
Click any swatch to exploreHarmonies
Accessibility
How this color appears to viewers with the four major color-vision-deficiency types. Computed via the Machado (2009) physiologically-based model. If a tile matches the original, the color reads the same to that viewer.
The color used as foreground text against pure white and pure black, with the contrast ratio and WCAG 2.1 grade. Aim for AA (4.5:1) for body text and AA Large (3:1) for 18 pt+ headlines; AAA (7:1) is the gold standard for long-form reading surfaces.
Wide gamut
The CSS Color 4 wide-gamut form of this color. Both swatches render the same color on every display — the P3 form only diverges from sRGB when a designer pushes channels outside sRGB's reach.
Moderately saturated colors gain a small bump in P3 — the difference is usually visible side-by-side on wide-gamut hardware but won't change the character of the color.