CSS Grid for html5j

Introducing 
CSS Grid Layout
Rachel Andrew
HTML 5j Web Platform Division, Tokyo

Rachel Andrew
CSS Working Group Invited Expert
Google Developer Expert for Web Technologies
Co-founder Perch CMS: https://grabaperch.com
Contact: me@rachelandrew.co.uk
rachelandrew.co.uk
@rachelandrew

Defining a Grid
- display: grid;
- display: inline-grid;
With a grid defined on the
parent element, all direct
children become Grid
Items.
.cards {
display: grid;
}

Defining a Grid
- grid-template-columns
- grid-template-rows
With these properties we
define an explicit grid. This
one has 3 column tracks
and 3 row tracks.
http://cssgrid.me/05161
.cards {
display: grid;
grid-template-columns: 250px 250px 250px;
grid-template-rows: 200px 200px 200px;
}

Defining a Grid
- grid-column-gap
- grid-row-gap
- grid-gap
We can create a gap
between rows and
columns. This gap acts
much like column-gap in
multiple column layout.
.cards {
display: grid;
grid-template-columns: 250px 250px 250px;
grid-gap: 20px;
}

Defining a Grid
The fr unit is a fraction
unit, representing a
fraction of the available
space in the container.
I have created 3 equal
width columns, each 1
space.
.cards {
display: grid;
grid-template-columns: 1fr 1fr 1fr;
grid-gap: 20px;
}

Defining a Grid
We have created 3
columns, the units add up
to 4. The space is spilt into
4 equal parts, the first 2
tracks are given 1 part, the
fine track 2 parts.
.cards {
display: grid;
grid-template-columns: 1fr 1fr 2fr;
grid-gap: 20px;
}

Defining a Grid
You can mix fraction units
with other length units.
Any tracks with a fraction
unit share the space left
after fixed size tracks and
the gaps have been
defined.
.cards {
display: grid;
grid-template-columns: 500px 1fr 2fr;
grid-gap: 20px;
}

Defining a Grid
The repeat syntax lets us
define a repeating pattern
of tracks.
Here we are creating 3 1fr
column tracks.
.cards {
display: grid;
grid-template-columns: repeat(3, 1fr);
grid-gap: 20px;
}

Defining a Grid
The explicit grid is the one
we define with rows and
columns. If we didn’t define
rows however grid would
great implicit row tracks
for us.
These will be auto sized by
default.
.cards {
display: grid;
grid-gap: 20px;
}

Defining a Grid
We can define the size of
implicit rows and column
with the properties:
- grid-auto-rows
- grid-auto-columns
.cards {
display: grid;
grid-auto-rows: 200px;
grid-gap: 20px;
}

Defining a Grid
Use the auto-fill keyword
and grid will create as
many tracks that will fit
into the container.
.cards {
display: grid;
grid-template-columns: repeat(auto-fill, 200px);
grid-gap: 20px;
}

Defining a Grid
The minmax() function
enables the creation of
flexible grids. The first
value is the minimum size
of the Grid Track, the
second the max size - set
that to 1fr to allow the
track to take up remaining
space.
.cards {
display: grid;
grid-template-columns: repeat(auto-fill, minmax(200px,1fr));
grid-gap: 20px;
}

Grid Track
A Grid Track is the space between two
Grid Lines. Tracks can be horizontal or
vertical (rows or columns).
The highlighted Grid Track is between
Row Lines 2 and 3.

Grid Lines
Lines can be horizontal or vertical. They
are referred to by number and can be
named.
Highlighted is Column Line 2.

Grid lines relate to writing mode. In
a right to left language such as
Arabic the first column line is the
right-hand line.

Grid Cell
The smallest unit on our grid, a Grid Cell
is the space between four Grid Lines. It’s
just like a table cell.
The highlighted Grid Cell is between row
lines 2 and 3 and column lines 2 and 3.

Grid Area
Any area of the Grid bound by 4 Grid
Lines. It can contain many Grid Cells.
The highlighted Grid Area is between
row lines 1 and 3, column lines 2 and 4.

Using line numbers
I have created a grid with 3
column tracks and 2 row
tracks.
With no placement our
blocks lay out one per grid
cell.
.cards {
display: grid;
grid-gap: 20px;
grid-template-columns: repeat(3,1fr);
grid-auto-rows: 200px;
}
1 2 3

Using line numbers
To place an item on the grid
I specify start and end lines
using new properties:
- grid-column-start
- grid-column-end
- grid-row-start
- grid-row-end
.card:nth-child(1) {
grid-column-start: 2;
grid-column-end: 4;
grid-row-start: 1;
grid-row-end: 3;
}
1
2
3

Using line numbers
These can be expressed as
a shorthand:
- grid-column
- grid-row
grid-column: 2 / 4;
grid-row: 1 / 3;
}
1
2
3

Using line numbers
They can be expressed as
one line using grid-area,
the order of the values is:
- grid-row-start
- grid-column-start
- grid-row-end
- grid-column-end
grid-area: 1 / 2 / 3 / 4;
}
1
2
3

Using line names
We name lines when
creating the grid. The name
goes in square brackets.
.cards {
display: grid;
grid-gap: 20px;
grid-template-columns: [side-start] 1fr
[main-start] 1fr 1fr
[main-end];
grid-template-rows: [main-start] 200px 200px
[main-end];
}

Using line names
Use the name instead of
the line number as the
value of the placement
properties.
grid-column: main-start / main-end;
grid-row: main-start / main-end;
}

Lines define Grid Areas
By creating lines named
main-start and end for
rows and columns, grid has
created me a named grid
area called ‘main’.
I can use that to position
my element rather than the
line numbers or names.
.cards {
display: grid;
grid-gap: 20px;
grid-template-columns: [side-start] 1fr
[main-start] 1fr 1fr
[main-end];
grid-template-rows: [main-start] 200px 200px
[main-end];
}
grid-area: main;
}

Defining Grid Areas
This time I haven’t named
my lines, I’ve just given
each element a name.
grid-area: main;
}
grid-area: side1;
}
grid-area: side2;
}

grid-template-areas
I then use these names to
describe my layout as the
value of grid-template-
areas.
.cards {
display: grid;
grid-gap: 20px;
grid-template-rows: 200px 200px;
grid-template-areas: "side1 main main"
"side2 main main";
}
mainside1
side2
main
main main

http://dev.w3.org/csswg/css-grid/#grid-item-placement-algorithm
“The following grid item placement
algorithm resolves automatic positions of
grid items into definite positions, ensuring
that every grid item has a well-defined grid
area to lay out into.”

A list containing images.
The landscape images are
inside a list item with a
class of ‘landscape’.
<ul class="wrapper">
<li><h3>1.</h3>
<img src="gallery1.jpg" alt="Balloons"></li>
<li class="landscape"><h3>2.</h3>
<li><h3>4.</h3>
<li><h3>7.</h3>
<li><h3>7.</h3>
</ul>

I have created a grid of
four equal columns.
.wrapper {
display: grid;
grid-template-columns: 1fr 1fr 1fr 1fr;
}

When using automatic
placement we can create
rules for items in our
document - for example
displaying portrait and
landscape images
differently.
.wrapper {
display: grid;
}
.landscape {
grid-column-end: span 2;
}

grid-auto-flow
The default value of grid-auto-flow is
sparse. Grid will move forward placing
items skipping cells if items do not fit .

With a dense packing
mode grid will move items
out of source order to
backfill spaces.
.wrapper {
display: grid;
grid-auto-flow: dense;
}
.landscape {
grid-column-end: span 2;
}

grid-auto-flow
With grid-auto-flow dense items are
displayed out of source order. Grid
backfills any suitable gaps.

Power and responsibility
• Good = creating the most accessible source
order and using Grid or Flexbox to get the
optimal display for each device.
• Bad = using Grid or Flexbox as an excuse to
forget about the source.
• Terrible - stripping out semantic elements to
make everything a grid or flex item.

https://www.w3.org/TR/css-grid-1/#placement-a11y
Correct source order is important for
speech, for sequential navigation (such
as keyboard navigation), and non-CSS
UAs such as search engines, tactile
browsers, etc. Grid placement only
affects the visual presentation!

http://adrianroselli.com/2015/10/html-source-order-vs-css-display-order.html

Léonie Watson | On CSS accessibility
and drinking tea | CSS Day 2016
https://vimeo.com/180566024
Also see:  
http://tink.uk/flexbox-the-keyboard-navigation-disconnect/

Is Grid a competing specification to Flexbox?

When should we use Grid instead of
Flexbox?

Flexbox is for 1 dimensional layout -
a column OR a row.
Grid is for 2 dimensional layout -
both columns AND rows.

Wrapping list items using
flexbox.
.flex {
display: flex;
flex-wrap: wrap;
margin: 0 -10px;
}
.flex li {
flex: 1 1 200px;
margin: 10px;
}

Wrapping list items with
Grid Layout.
.grid {
display: grid;
grid-template-columns:
repeat(auto-fill, minmax(200px 1fr));
grid-gap: 20px;
}

Using the minmax()
function with grid-auto-
rows.
.home-hero {
display: grid;
grid-gap: 1px;
grid-auto-rows: minmax(150px, auto);
}

An item on the grid can
become a grid or flex
container itself.
In this case I am using
flexbox and auto margins
to push my content to the
bottom of the box.
.special {
display: flex;
flex-direction: column;
}
.special h3{
margin-top: auto;
}

Animatable
• grid-template-columns
• grid-template-rows
• grid-gap
• grid-column-gap
• grid-row-gap

https://drafts.csswg.org/css-grid/#track-sizing
grid-template-* animatable as a simple list
of length, percentage, or calc, provided the
only differences are the values of the length,
percentage, or calc components in the list.

https://drafts.csswg.org/css-grid/#gutters
grid-gap, grid-column-gap, grid-row-gap
animatable as length, percentage, or calc.

March 2017 March 2017 March 2017 March 2017 March 2017 Soon!

But, what about browsers with  
no support?

http://caniuse.com/#feat=css-featurequeries

A feature query looks like
a media query.
Test for a property and
value pair.
// code for non-grid browsers
@supports (display: grid) {
// grid layout code here
}

To use feature queries
• Write CSS for browsers without support
• Override those properties inside the feature
queries
• See https://hacks.mozilla.org/2016/08/using-
feature-queries-in-css/

You don’t have to turn your entire layout
over to grid. Look at using it for small UI
elements, as an enhancement.

More code plus video tutorials!
I am creating a list of examples, video tutorials and information at:
http://gridbyexample.com

Think of a question later? AMA.
https://github.com/rachelandrew/cssgrid-ama

Thank you!
https://rachelandrew.co.uk/speaking/event/html5j-japan
 
@rachelandrew

CSS Grid for html5j

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