d2lang/d2 · error

unknown style key: %s

Error message

unknown style key: %s

What it means

SetStyle on a d2graph object only recognizes known style keys (fill, stroke, font, text-transform, etc.). An unrecognized key hits the default branch and returns "unknown style key" naming the key.

Source

Thrown at d2graph/d2graph.go:492

	case "double-border":
		if s.DoubleBorder == nil {
			break
		}
		_, err := strconv.ParseBool(value)
		if err != nil {
			return errors.New(`expected "double-border" to be true or false`)
		}
		s.DoubleBorder.Value = value
	case "text-transform":
		if s.TextTransform == nil {
			break
		}
		if !go2.Contains(d2ast.TextTransforms, strings.ToLower(value)) {
			return fmt.Errorf(`expected "text-transform" to be one of (%s)`, strings.Join(d2ast.TextTransforms, ", "))
		}
		s.TextTransform.Value = value
	default:
		return fmt.Errorf("unknown style key: %s", key)
	}

	return nil
}

type ContainerLevel int

func (l ContainerLevel) LabelSize() int {
	// Largest to smallest
	if l == 1 {
		return d2fonts.FONT_SIZE_XXL
	} else if l == 2 {
		return d2fonts.FONT_SIZE_XL
	} else if l == 3 {
		return d2fonts.FONT_SIZE_L
	}
	return d2fonts.FONT_SIZE_M
}

View on GitHub (pinned to 0d69dca6f5)

Solutions

1. Correct the key spelling against D2's documented style keys
2. Use the D2 equivalent name (e.g. "stroke-width" not "strokeWidth")
3. Upgrade D2 if the key was added in a newer version

Example fix

// before
x.style.colour: red
// after
x.style.fill: red

var knownStyleKeys = map[string]bool{"fill":true, "stroke":true, "font":true, "font-size":true, "text-transform":true /* ... */}
if !knownStyleKeys[key] { /* reject before SetStyle */ }

func knownStyleKey(k string) bool {
	switch k { case "fill","stroke","stroke-width","fill-pattern","font","font-size","text-transform","border-radius","double-border", "shadow","opacity","multiple","animated","link","stroke-dash","bold","italic","underline","font-color": return true }
	return false
}

if err := obj.SetStyle(key, val); err != nil {
	return fmt.Errorf("check style key %q against d2 docs: %v", key, err)
}

When it happens

Trigger: Passing any key that is not in SetStyle's switch — e.g. `style.colour`, `style.bg-color`, or a misspelled known key like `style.storke-width`.

Common situations: Typos in .d2 style blocks, using CSS property names instead of D2's keys, or using keys from newer/older D2 versions than the installed binary.

Related errors

• expected "shadow" to be true or false
• expected "3d" to be true or false
• expected "multiple" to be true or false
• expected "font-size" to be a number between 8 and 100
• expected "font-color" to be a valid named color ("orange"),

AI-assisted analysis of d2lang/d2@0d69dca6f5 (2026-08-31). Data as JSON: /api/errors/6f7184438e99395a. Report an issue: GitHub.