font-optical-sizing

The font-optical-sizing CSS sets whether text rendering is optimized for viewing at different sizes. This only works for fonts that have an optical size variation axis.

For example, small text sizes are often rendered with thicker strokes and larger serifs, whereas larger text is often rendered more delicately with more contrast between thicker and thinner strokes.

Syntax

/* keyword values */
font-optical-sizing: none; 
font-optical-sizing: auto; /* default */

/* Global values */
font-optical-sizing: inherit;
font-optical-sizing: initial;
font-optical-sizing: unset;

Values

none

The browser will not modify the shape of glyphs for optimal viewing.

auto

The browser will modify the shape of glyphs for optimal viewing.

Formal syntax

auto | none

Examples

<p class="optical-sizing">This paragraph is optically sized.
 This is the default across browsers.</p>

<p class="no-optical-sizing">This paragraph is not optically sized.
 You should see a difference in supporting browsers.</p>

@font-face {
    src: url('AmstelvarAlpha-VF.ttf');
    font-family:'Amstelvar';
    font-style: normal;
}

p {
  font-size: 36px;
  font-family: Amstelvar;
}

.no-optical-sizing {
  font-optical-sizing: none;
}

Specifications

Browser compatibilityUpdate compatibility data on GitHub