Create Flexible Layouts Using auto-fill

Summary

The auto-fill function can be used to automatically insert rows/columns of a desired size as possible.

Final Code

<style>
  .item1{background:LightSkyBlue;}
  .item2{background:LightSalmon;}
  .item3{background:PaleTurquoise;}
  .item4{background:LightPink;}
  .item5{background:PaleGreen;}

  .container {
    font-size: 40px;
    min-height: 100px;
    width: 100%;
    background: LightGray;
    display: grid;
    /* Only change code below this line */

    grid-template-columns: repeat(auto-fill, minmax(60px, 1fr));

    /* Only change code above this line */
    grid-template-rows: 1fr 1fr 1fr;
    grid-gap: 10px;
  }

  .container2 {
    font-size: 40px;
    min-height: 100px;
    width: 100%;
    background: Silver;
    display: grid;
    grid-template-columns: repeat(3, minmax(60px, 1fr));
    grid-template-rows: 1fr 1fr 1fr;
    grid-gap: 10px;
  }
</style>
<div class="container">
  <div class="item1">1</div>
  <div class="item2">2</div>
  <div class="item3">3</div>
  <div class="item4">4</div>
  <div class="item5">5</div>
</div>
<div class="container2">
  <div class="item1">1</div>
  <div class="item2">2</div>
  <div class="item3">3</div>
  <div class="item4">4</div>
  <div class="item5">5</div>
</div>