override-colors

/* 基本的な構文 */
override-colors: <index of color> <color>;
/* 色名の使用 */
override-colors: 0 red;
/* 16 進色の使用 */
override-colors: 0 #f00;
/* rgb の使用 */
override-colors: 0 rgb(255 0 0);
/* 複数の色のオーバーライド */
override-colors:
  0 #f00,
  1 #0f0,
  2 #00f;
/* 複数の色のオーバーライドを読みやすく */
override-colors:
  0 #f00,
  1 #0f0,
  2 #00f;

<section class="hats">
  <div class="hat">
    <h2>Original Hat</h2>
    <div class="emoji">🎩</div>
  </div>
  <div class="hat">
    <h2>Red Hat</h2>
    <div class="emoji red-hat">🎩</div>
  </div>
</section>

.hats {
  display: flex;
  flex-direction: row;
  justify-content: space-around;
}

@font-face {
  font-family: "Noto Color Emoji";
  font-style: normal;
  font-weight: 400;
  src: url(https://fonts.gstatic.com/l/font?kit=Yq6P-KqIXTD0t4D9z1ESnKM3-HpFabts6diywYkdG3gjD0U&skey=a373f7129eaba270&v=v24)
    format("woff2");
}
.emoji {
  font-family: "Noto Color Emoji";
  font-size: 3rem;
}
@font-palette-values --red {
  font-family: "Noto Color Emoji";
  override-colors:
    0 rgb(74 11 0),
    1 rgb(149 22 1),
    2 rgb(183 27 1),
    3 rgb(193 28 1),
    4 rgb(230 34 1);
}
.red-hat {
  font-palette: --red;
}

<h2 class="normal-palette">Normal Palette</h2>
<h2 class="override-palette">Override Palette</h2>

@font-face {
  font-family: "Rocher";
  src: url("[path-to-font]/RocherColorGX.woff2") format("woff2");
}
h2 {
  font-family: "Rocher";
}
@font-palette-values --override-palette {
  font-family: "Rocher";
  base-palette: 3;
}
@font-palette-values --override-palette {
  font-family: "Rocher";
  base-palette: 3;
  override-colors: 0 rebeccapurple;
}
.normal-palette {
  font-palette: --normal-palette;
}
.override-palette {
  font-palette: --override-palette;
}