未设置 | unset

.foo {
  color: blue;
}
.bar {
  color: green;
}

p {
  color: red;
}
.bar p {
  color: unset;
}

<p>This text is red.</p>
<div class="foo">
  <p>This text is also red.</p>
</div>
<div class="bar">
  <p>This text is green (default inherited value).</p>
</div>

div {
  border: 1px solid green;
}

p {
  border: 1px solid red;
}

.bar p {
  border-color: unset;
}

<p>This text has a red border.</p>
<div>
  <p>This text has a red border.</p>
</div>
<div class="bar">
  <p>This text has has a black border (initial default, not inherited).</p>
</div>