CSS: “padding-bottom”: X is not a “padding-bottom” value.

An invalid value was assigned to the padding-bottom CSS property inside a style attribute, and the W3C validator rejected it.

The padding-bottom property accepts a length (e.g., 10px, 2em), a percentage (e.g., 5%), or the keyword inherit. Values like auto, bare numbers without units, or unrecognized keywords are not valid. A common mistake is writing padding-bottom: 10 instead of padding-bottom: 10px, or using a value meant for a different property.

The validator specifically checks inline styles in style attributes against CSS grammar rules. Even if a browser silently ignores the bad value, the markup is still invalid.

Invalid example

<div style="padding-bottom: auto;">
  Content here
</div>

The value auto is not valid for padding-bottom.

Valid example

<div style="padding-bottom: 10px;">
  Content here
</div>

Use a supported value: a length with a unit (px, em, rem, %, etc.) or 0 (which does not require a unit).

Learn more:

MDN Reference

CSS padding-bottom

→

MDN Reference

CSS padding

→