font-synthesis-position

/* Keyword values */
font-synthesis-position: auto;
font-synthesis-position: none;

/* Global values */
font-synthesis-position: inherit;
font-synthesis-position: initial;
font-synthesis-position: revert;
font-synthesis-position: revert-layer;
font-synthesis-position: unset;

<p>
  These are the default position <span class="super">superscript</span>,
  position <span class="sub">subscript</span>, <strong>bold</strong> and
  <em>oblique</em> typefaces.
</p>

<p class="no-syn">
  The positions <span class="super">superscript</span> and
  <span class="sub">subscript</span> typeface is turned off here but not the
  <strong>bold</strong> and <em>oblique</em> typefaces (on browsers that support
  <code>font-synthesis-position</code>).
</p>

@import url("https://fonts.googleapis.com/css2?family=Montserrat&display=swap");

* {
  font-family: "Montserrat", sans-serif;
}
.super {
  font-variant-position: super;
}
.sub {
  font-variant-position: sub;
}
.no-syn {
  font-synthesis-position: none;
}