Verificação HTML: CSS: “font-stretch”: “bold” is not a “font-stretch” value.

Sobre este problema de CSS

The font-stretch property selects a normal, condensed, or expanded face from a font family. Its valid keyword values are ultra-condensed, extra-condensed, condensed, semi-condensed, normal, semi-expanded, expanded, extra-expanded, and ultra-expanded. It also accepts percentage values (e.g., 50% to 200%). The value bold doesn’t fit into any of these categories because it describes font weight (thickness of strokes), not font width (how narrow or wide the characters are).

This error usually happens due to one of two mistakes:

Confusing font-stretch with font-weight: You intended to make text bold but accidentally used the wrong property.
Typo or copy-paste error in the font shorthand: When writing shorthand font declarations, the various sub-properties can easily get mixed up.

The W3C validator flags this because browsers will ignore invalid CSS values, meaning your intended styling won’t be applied. Fixing it ensures your styles work as expected across all browsers and pass validation.

How to Fix It

If you want bold text, use font-weight: bold (or numeric values like 700).
If you want wider or narrower characters, use font-stretch with a valid value like condensed or expanded.
If you need both, apply each property separately or use the font shorthand correctly.

Examples

Incorrect: Using `bold` with `font-stretch`

This triggers the validation error because bold is not a valid font-stretch value:

<p style="font-stretch: bold;">This text won't render as expected.</p>

Fixed: Using `font-weight` for boldness

If the intent was to make the text bold, switch to font-weight:

<p style="font-weight: bold;">This text is bold.</p>

Fixed: Using `font-stretch` correctly for width

If the intent was to adjust the character width, use a valid font-stretch value:

<p style="font-stretch: expanded;">This text uses an expanded font face.</p>

Using both properties together

You can combine font-weight and font-stretch when you need both bold text and a different font width:

<style>
  .styled-text {
    font-weight: bold;
    font-stretch: condensed;
    font-family: Arial, sans-serif;
  }
</style>

<p class="styled-text">This text is bold and condensed.</p>

Valid `font-stretch` values reference

Here’s a quick overview of all valid keyword values for font-stretch:

<style>
  .condensed { font-stretch: condensed; }
  .normal-width { font-stretch: normal; }
  .expanded { font-stretch: expanded; }
  .custom-width { font-stretch: 75%; }
</style>

<p class="condensed">Condensed text</p>
<p class="normal-width">Normal width text</p>
<p class="expanded">Expanded text</p>
<p class="custom-width">75% width text</p>

Note that font-stretch only works if the selected font family includes condensed or expanded faces. If the font doesn’t have these variations, the property will have no visible effect even with valid values.