Mix grid autolayout with fixed column and column positions

Question

I have the following HTML with CSS grid

<div id="grid">
    <div class="main-item">Main</div>
</div>

#grid {
    display: grid;
    grid-template-columns: repeat(5, auto);
    text-align: center;
}

#grid > * {
    border: 1px solid blue;
    padding: 20px;
}

#grid > .main-item {
    grid-row: 3;
    grid-column: 3 / 5;
    background: rgba(0, 0, 0, 0.2);
}

The important part is that .main-item has a fixed position in the grid.

I now add 25 cells to the grid.

const grid = document.querySelector("#grid");

for (let i = 0; i < 25; i++) {
    const item = document.createElement("div");
    item.innerText = i.toString();
    grid.append(item);
}

The problem is that I want these elements to ignore the position of .main-item (treat it as not existing). However, CSS now corrects this and makes the elements flow around .main-item. I want the following secondary behavior:

I was able to correct this by setting style.gridRow and style.gridColumn in JavaScript

item.style.gridRow = (Math.floor(i / 5) + 1).toString();
item.style.gridColumn = ((i % 5) + 1).toString();

Is there a way to do this without setting all the other elements in JS? Is there CSS to prevent fixed elements from affecting flow correction?

Code Pen Link

Answer 1

You can give the grid a relative position and absolutely position specific grid items.

const grid = document.querySelector("#grid");
for (let i = 0; i < 25; i++) {
    const item = document.createElement("div");
    item.innerText = i;
    grid.append(item);
}

#grid {
    display: grid;
    grid-template-columns: repeat(5, auto);
    text-align: center;
    position: relative;
}

#grid > * {
    border: 1px solid blue;
    padding: 20px;
}

#grid > .main-item {
    position: absolute;
    left: 0;
    right: 0;
    grid-row: 3;
    grid-column: 3 / 5;
    background: rgba(0, 0, 0, 0.2);
}

<div id="grid">
    <div class="main-item">Main</div>
</div>