IE11 doesn't support grid gutters.

[MikeVaz]

New spec
https://www.w3.org/TR/css-grid-1/#gutters

Older IE11 spec doesn't have it:
https://www.w3.org/TR/2011/WD-css3-grid-layout-20110407/#grid-concepts

[MikeVaz]

In powergrid 🔢 we use box models of grid items to compensate.

HTML

<div class="pg-grid">
    <div>1</div>
    <div>2</div>
    <div>3</div>
    <div>4</div>
    <div>5</div>
    <div>6</div>
</div>

CSS

...

/* Decorating grid items with space */
.pg-grid>div {
  ...
  border: 1px solid #c0c0c0;
  padding: 10px;
  margin: 5px;
}

/* Grid lines template */
.pg-grid {
  display: grid;
  display: -ms-grid;
  grid-template-columns: 100px 100px 100px;
  -ms-grid-columns: 100px 100px 100px;
  grid-template-rows: 100px 100px;
  -ms-grid-rows: 100px 100px;
}

Demo