Auto-fill or auto-fit?

One of my favorite snipptes of CSS Grid is the following one:

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
}

I once spent a significant amount of time wondering why it would create more columns than grid-items. Turns out, there is a subtle difference between auto-fill and auto-fit. If you want to make sure that your grid-items always span at least the full width of your grid you need to use auto-fit for that.

Sara Soueidan has kindly written a comprehensive explanation over at CSS-Tricks. Thank you, Sara!