sticky position on css grid items

Question

I've looked at other examples of this on here but can't find one that makes this work. I want the sidebar (section) to be sticky while the page scrolls. the position: sticky works if I put it on the nav, so my browser def supports it.

main {
  display: grid;
  grid-template-columns: 20% 55% 25%;
  grid-template-rows: 55px 1fr;
}

nav {
  background: blue;
  grid-row: 1;
  grid-column: 1 / 4;
}

section {
  background: grey;
  grid-column: 1 / 2;
  grid-row: 2;
  position: sticky;
  top: 0;
  left: 0;
}

article {
  background: yellow;
  grid-column: 2 / 4;
}

article p {
  padding-bottom: 1500px;
}

<main>
  <nav></nav>
  <section>
    hi
  </section>
  <article>
    <p>hi</p>
  </article>
</main>

Answer 1

section needs a height in order for sticky to achieve your desired effect and because of potential quirks with sticky (i.e section would push up over grid-row 1 when you reach the bottom of the page), I'd start section on grid-row 1 rather than 2 along with a wrapper container.

assuming your nav is also sticky, I'd set its z-index so it's on top of the section.

I'd also suggest using @support to use the fixed solutions others have mentioned.

      main {
        display: grid;
        grid-template-columns: 20% 55% 25%;
        grid-template-rows: 55px 1fr;
      }
      
      nav {
        background: blue;
        grid-row: 1;
        grid-column: 1 / 4;
        z-index: 2;
        position: sticky;
        top: 0;
      }
      
      section {
        background: grey;
        grid-column: 1 / 2;
        grid-row: 1;
        position: sticky;
        top: 0;
        left: 0;
        height: 100vh;
      }
      
      section #contents {
        position: relative;
        top: 55px;
      }
      
      article {
        background: yellow;
        grid-column: 2 / 4;
      }

      article p {
        padding-bottom: 1500px;
      }

<main>
  <nav></nav>  
  <section>
    <div id="contents">
      contents
    </div>
  </section>
  <article>
    <p>article</p>
  </article>
</main>

Answer 2

the problem you are facing here is, that your section block consumes the full height. so it won't stick, since it is too large to do so. you would need to put a child element inside your section and give that your sticky attributes, to make it work. based on your example, i simply wrapped your 'hi' inside a div.

main {
  display: grid;
  grid-template-columns: 20% 55% 25%;
  grid-template-rows: 55px 1fr;
}

nav {
  background: blue;
  grid-row: 1;
  grid-column: 1 / 4;
}

section {
  background: grey;
  grid-column: 1 / 2;
  grid-row: 2;
}

section div {
  position: sticky;
  top: 0;
}

article {
  background: yellow;
  grid-column: 2 / 4;
}

article p {
  padding-bottom: 1500px;
}

<main>
  <nav></nav>
  <section>
    <div>
      hi
    </div>
  </section>
  <article>
    <p>hi</p>
  </article>
</main>

Answer 3

Use position: fixed for your section and nav. Maybe, this is similar to what you want:

body {
  margin: 0;
}

nav {
  background: blue;
  height: 80px;
  z-index: 9;
  width: 100%;
  position: fixed;
}

article {
  width: 100%;
  display: grid;
  grid-template-columns: 20vw auto;
}

article p {
  padding-bottom: 1500px;
}

section {
  position: fixed;
  width: 20vw;
  background: grey;
  height: 100%;
  top: 80px;
}

.content {
  margin-top: 80px;
  position: relative;
  grid-column-start: 2;
  background: yellow;
}

<main>
  <nav></nav>
  <section>
    hi
  </section>
  <article>
    <div class="content">
      <p>hi</p>
    </div>
  </article>
</main>