Horizontal border across entire row of CSS GRID

Question

I need to use a grid layout but also need a horizontal line separating each row.

The only thing I've been able to find is applying a border to each cell, but this only works if there are enough cells to fill each row.

.wrapper {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 100px);
}

.box {
  border-bottom: 2px solid #ffa94d;
  padding: 1em;
}

<div class="wrapper">
  <div class="box">One</div>
  <div class="box">Two</div>
  <div class="box">Three</div>
  <div class="box">Four</div>
</div>

Is there a way to fix the above so that the entire row has a border?

Answer 1

Add a grid-gap equal to the width of your border then consider gradient to achieve this:

.wrapper {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 100px);
  grid-row-gap:2px;
  background:
    repeating-linear-gradient(to bottom,
      transparent 0,
      transparent 100px,
      #ffa94d 100px,
      #ffa94d 102px /*+2px here*/
    );
}

.box {
  padding: 1em;
}

<div class="wrapper">
  <div class="box">One</div>
  <div class="box">Two</div>
  <div class="box">Three</div>
  <div class="box">Four</div>
</div>

Another idea is to consider a pseudo-element that you add to the 1st,4th,7th .. (3n + 1)th element:

.wrapper {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 100px);
  overflow:hidden;
}

.box {
  position:relative;
  padding: 1em;
}
.box:nth-child(3n + 1)::after {
  content:"";
  position:absolute;
  bottom:0px;
  left:0;
  width:100vw;
  height:2px;
  background:#ffa94d;
}

<div class="wrapper">
  <div class="box">One</div>
  <div class="box">Two</div>
  <div class="box">Three</div>
  <div class="box">Four</div>
</div>