Property Reference - CSS Reference - page 299

Name
rest-after
Values:
none | x-weak | weak | medium | strong | x-strong | <time>
Initial value:
User agent-dependent
Applies to:
All elements
Inherited:
No
Computed value:
Not specified, but likely an absolute time value
Description:
Defines the length of a rest that follows the audio rendering of an element's content. A rest
is an interval in which no content is audibly rendered, although background sounds may still
be audible. The rest is rendered after the element's content but before any cue that follows the
element (see cue-after and related properties).
Examples:
th {rest-after: 0.5s;}
strong {rest-after: 250ms;}