Adding a class "collapse" to flex grid creates uneven spacing - css

Question

So, I am creating a grid system based on flexbox and everything is going quite swimmingly. The basics of my grid are:
<div class="row">
<div class="column"><p>Column</p></div>
<div class="column"><p>Column</p></div>
<div class="column"><p>Column</p></div>
</div>
And in my css:
.row {
margin: 10px 0;
display: flex;
flex-wrap: wrap;
}
.column {
padding: 10px;
flex: 1 1 0%;
}
Essentially, this makes the columns quite fluid, and they shrink/grow to fill all available space. This is great for me as I need to use this throughout various projects where I can't quite customize the grid for every single one. However, I have run into a small "issue". I was going to create a class called ".collapse" so I could collapse the left/right padding to have some columns fit right next together (for example: If I wanted a div with a background color (by adding a color class to the column=> .column .green) flush to an image in the next column). However, the spacing is all out of wack compared to row/columns above it.
<div class="row">
<div class="column purple collapse"><p>Column</p></div>
<div class="column red collapse"><p>Column</p></div>
<div class="column purple collapse"><p>Column</p></div>
<div class="column red collapse"><p>Column</p></div>
</div>
example screenshot here
As you can see in my little example mockup, they do kinda line up, but the right and left margins have "decreased". Is there any smart way around this? I tried adding "left/right margins" to the first-of-type and last-of-type, but this just gets a bit hacky as then anything added in between start having odd alignment issues.

Answer 1

For this kind of grid system, you usually would discourage using structural styling on the grid cells directly, and it lets you do something like this:
.row {
display: flex;
flex-flow: row wrap;
list-style: none;
padding: 0;
margin-left: -10px;
}
.column {
flex: 1 0 0;
padding-left: 10px;
}
.collapse { margin-left: 0; }
.collapse > .column { padding-left: 0; }
.red,
.purple {
padding: 10px;
margin-bottom: 10px;
}
.red { background-color: red; }
.purple { background-color: purple; }
<div class="row">
<div class="column">
<div class="purple">
<p>Column</p>
</div>
</div>
<div class="column">
<div class="red">
<p>Column</p>
</div>
</div>
<div class="column">
<div class="purple">
<p>Column</p>
</div>
</div>
<div class="column">
<div class="red">
<p>Column</p>
</div>
</div>
</div>
<div class="row collapse">
<div class="column">
<div class="purple">
<p>Column</p>
</div>
</div>
<div class="column">
<div class="red">
<p>Column</p>
</div>
</div>
<div class="column">
<div class="purple">
<p>Column</p>
</div>
</div>
<div class="column">
<div class="red">
<p>Column</p>
</div>
</div>
</div>
This approach uses no margins on the outer ends, which I find way more convenient.
It's worth noting that this kind os system is not all that useful anymore, with the advent of CSS Grid Layout, but there you have it.
On a side note, 0 is always 0, and it never needs a unit.