How to stretch middle column in a 3 column grid setup

Question

I am trying to setup a header with a single row and three columns 'grid' system. Such as :

* {box-sizing: border-box;}

.wrapper {
    border: 2px solid #f76707;
    border-radius: 5px;
    background-color: #fff4e6;
}

.wrapper > div {
    border: 2px solid #ffa94d;
    border-radius: 5px;
    background-color: #ffd8a8;
    padding: 1em;
    color: #d9480f;
}
.wrapper {
  display: grid;
  grid-template-columns: 100px,1fr,100px;
  grid-template-rows: 1fr;

  grid-template-areas: "a b c";

}
.item1 {
  grid-area: a;
  justify-self:start;
}
.item2 {
  grid-area: b;
  justify-self:stretch;
}
.item3 {
  grid-area: c;
  justify-self:end;
}

<div class="wrapper">
  <div class="item1">Item 1</div>
  <div class="item2">Item 2</div>
  <div class="item3">Item 3</div>
</div>

However the middle column will only center rather than stretch. Here's the fiddle https://jsfiddle.net/mmo7534/pnxtys79/2/

How can I make it stretch ?

Answer 1

Remove the commas from your grid-template-columns value, then you don't have to worry about styling the individual items:

* {
  box-sizing: border-box;
}

.wrapper {
  border: 2px solid #f76707;
  border-radius: 5px;
  background-color: #fff4e6;
  display: grid;
  grid-template-columns: 100px 1fr 100px;
}

.wrapper>div {
  border: 2px solid #ffa94d;
  border-radius: 5px;
  background-color: #ffd8a8;
  padding: 1em;
  color: #d9480f;
}

<div class="wrapper">
  <div class="item1">Item 1</div>
  <div class="item2">Item 2</div>
  <div class="item3">Item 3</div>

</div>