About This HTML Issue
A CSS border shorthand property has been assigned a value that the validator expects to be a color, but the value provided is not a recognized color.
This error typically appears when the border shorthand is missing a required component or has its values in an unexpected order. The border shorthand accepts up to three values: a width, a style, and a color. While the CSS specification allows these in any order, some validators and parsers can misinterpret values when the style keyword (such as solid, dashed, or none) is omitted.
A common cause is writing something like border: 1px black without a border style. The validator may try to interpret black or another value as filling the wrong role. Another cause is a typo in the color value itself, such as grren instead of green, or using a syntax the validator does not recognize.
Always include all three components in the border shorthand to avoid ambiguity: width, style, and color.
HTML examples
Invalid border value
<p style="border: 1px black">Some text</p>
The missing style keyword (solid, dashed, etc.) can cause the validator to misinterpret which value maps to which component.
Valid border value
<p style="border: 1px solid black">Some text</p>
Including the width (1px), style (solid), and color (black) removes any ambiguity. If a border style is not specified, the initial value is none, which means no border is rendered, so omitting it is almost certainly a mistake anyway.
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