Prevent content from expanding grid items

203
votes

TL;DR: Is there anything like table-layout: fixed for CSS grids?

I tried to create a year-view calendar with a big 4x3 grid for the months and therein nested 7x6 grids for the days.

The calendar should fill the page, so the year grid container gets a width and height of 100% each.

.year-grid {
  width: 100%;
  height: 100%;

  display: grid;
  grid-template: repeat(3, 1fr) / repeat(4, 1fr);
}

.month-grid {
  display: grid;
  grid-template: repeat(6, 1fr) / repeat(7, 1fr);
}

Here's a working example: https://codepen.io/loilo/full/ryXLpO/

For simplicity, every month in that pen there has 31 days and starts on a Monday.

I also chose a ridiculously small font size to demonstrate the problem:

Grid items (= day cells) are pretty condensed as there are several hundreds of them on the page. And as soon as the day number labels become too large (feel free to play around with the font size in the pen using the buttons on the upper left) the grid will just grow in size and exceed the page's body size.

Is there any way to prevent this behaviour?

I initially declared my year grid to be 100% in width and height so that's probably the point to start at, but I couldn't find any grid-related CSS properties that would've fitted that need.

Disclaimer: I'm aware that there are pretty easy ways to style that calendar just without using CSS Grid Layout. However, this question is more about the general knowledge on the topic than solving the concrete example.

3
cssgrid-layoutcss-grid
What do you want to happen instead? The font in each cell can just be whatever size and it never causes the grid cell size to increase? – Michael Coker
Exactly. Basically a more convenient way of what would happen if I set the sizes of the grid items to according percentage values instead of fractions. – Loilo
I'm basically looking for a grid-layouty version of table-layout: fixed (see: codepen.io/loilo/pen/dvxpvq?editors=1100) – Loilo
This the the biggest pain in the whole CSS Grid specification. Their needs to be a setting where grids areas cannot escape the dimensions of any of their parent grid containers! As is, it is a nightmare for deeply nested grid structures. – Lonnie Best

3 Answers

353
votes

By default, a grid item cannot be smaller than the size of its content.

Grid items have an initial size of min-width: auto and min-height: auto.

You can override this behavior by setting grid items to min-width: 0, min-height: 0 or overflow with any value other than visible.

From the spec:

6.6. Automatic Minimum Size of Grid Items

To provide a more reasonable default minimum size for grid items, this specification defines that the auto value of min-width / min-height also applies an automatic minimum size in the specified axis to grid items whose overflow is visible. (The effect is analogous to the automatic minimum size imposed on flex items.)

Here's a more detailed explanation covering flex items, but it applies to grid items, as well:

This post also covers potential problems with nested containers and known rendering differences among major browsers.

To fix your layout, make these adjustments to your code:

.month-grid {
  display: grid;
  grid-template: repeat(6, 1fr) / repeat(7, 1fr);
  background: #fff;
  grid-gap: 2px;
  min-height: 0;  /* NEW */
  min-width: 0;   /* NEW; needed for Firefox */
}

.day-item {
  padding: 10px;
  background: #DFE7E7;
  overflow: hidden;  /* NEW */
  min-width: 0;      /* NEW; needed for Firefox */
}

jsFiddle demo

1fr vs minmax(0, 1fr)

The solution above operates at the grid item level. For a container level solution, see this post:

92
votes

The previous answer is pretty good, but I also wanted to mention that there is a fixed layout equivalent for grids, you just need to write minmax(0, 1fr) instead of 1fr as your track size.

2
votes

The existing answers solve most cases. However, I ran into a case where I needed the content of the grid-cell to be overflow: visible. I solved it by absolutely positioning within a wrapper (not ideal, but the best I know), like this:


.month-grid {
  display: grid;
  grid-template: repeat(6, 1fr) / repeat(7, 1fr);
  background: #fff;
  grid-gap: 2px;  
}

.day-item-wrapper {
  position: relative;
}

.day-item {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 10px;

  background: rgba(0,0,0,0.1);
}

https://codepen.io/bjnsn/pen/vYYVPZv