HTML Guides for right

An invalid value was assigned to the CSS right property, meaning the validator does not recognize the value you provided.

The CSS right property specifies the horizontal offset of a positioned element from the right edge of its containing block. It only accepts specific value types: a length (e.g., 10px, 2em), a percentage (e.g., 50%), auto, inherit, initial, unset, or revert. Any other value — such as a typo, a missing unit, or an unsupported keyword — will trigger this validation error.

A common mistake is forgetting the unit after a number. In CSS, 0 is the only length value that can be written without a unit. Writing something like right: 10 instead of right: 10px is invalid. Another common cause is using an unrecognized keyword or passing a value meant for a different property.

Invalid Example

<div style="position: absolute; right: 10;">
  This box has an invalid right value.
</div>

The value 10 is missing a unit, so the validator rejects it.

Fixed Example

<div style="position: absolute; right: 10px;">
  This box is correctly positioned.
</div>

Adding a valid unit like px, em, rem, or % resolves the issue. If you intended no offset, use right: 0 or right: auto.