JSFiddle - React, Tailwind, and code Playground

HTML

<span>%版</span>
<div class="grid css-gap">
  <div>1fr</div>
  <div>2fr</div>
  <div>4fr</div>
  <div>8fr</div>
  <div>16fr</div>
</div>
<span>ダミー要素版</span>
<div class="grid dummy-gap">
  <div>1fr</div>
  <div class="gap"></div>
  <div>2fr</div>
  <div class="gap"></div>
  <div>4fr</div>
  <div class="gap"></div>
  <div>8fr</div>
  <div class="gap"></div>
  <div>16fr</div>
</div>

CSS

.grid.css-gap {
 display: grid;
 gap: calc(1 / 33 * 100%);
 grid-template-columns: 1fr 2fr 4fr 8fr 16fr;
}
.grid.dummy-gap {
 display: grid;
 gap: 0;
 grid-template-columns: 1fr 1fr 2fr 1fr 4fr 1fr 8fr 1fr 16fr;
}
.grid > div:not(.gap) {
  background: #8ff;
  border: solid 1px black;
}