ConFoo 2016: Making Sense of CSS Layout

Making Sense
of CSS Layout
Rachel Andrew, ConFoo 2016
https://www.ﬂickr.com/photos/nossreh/5510993121/

Rachel Andrew
Blogging about tech/business and other things at rachelandrew.co.uk
On Twitter and other places as @rachelandrew
Co-founder of Perch & Perch Runway CMS, see: grabaperch.com
Teaching CSS Layout at thecssworkshop.com
Google Developer Expert for Web Technologies
Contact: me@rachelandrew.co.uk

Modern CSS Layout?
• Floats
• Inline-block
• display: table
• Absolute & Relative positioning
• Frameworks … lots of frameworks

Snippet from Bootstrap
Grid mark-up. <div class="row">
<div class="col-md-8">
.col-md-8
<div class="row">
.col-md-6
</div>
.col-md-6
</div>
</div>
</div>
.col-md-4
</div>
</div>

The cost of taming layout methods
• Developer hours spent learning non-obvious
concepts.
• Compromises in terms of document semantics in
order to achieve responsive layouts.
• Needing to lean on frameworks to help with
complex maths.
• Adding markup to create grids
• Using preprocessors to abstract layout hacks

Our great hopes for layout
• Flexbox 
https://drafts.csswg.org/css-flexbox/
• CSS Grid Layout 
https://drafts.csswg.org/css-grid/
• Box Alignment 
https://drafts.csswg.org/css-align/

The new CSS for Layout
• Items in our layouts understand themselves as
part of an overall layout.
• True separation of document source order and
visual display.
• Precise control of alignment - horizontally and
vertically.
• Responsive and flexible by default.

Items in our layouts understand
themselves as part of a complete
layout.

http://alistapart.com/article/fauxcolumns

http://colintoh.com/blog/display-table-anti-hero

Flexbox
Full height columns with
flexbox, taking advantage
of default alignment values.
.wrapper {
display: flex;
}
.sidebar {
flex: 1 1 30%;
}
.content {
flex: 1 1 70%;
}

Grid Layout
Full height columns in CSS
Grid Layout.
.wrapper {
display: grid;
grid-template-columns: 30% 70%;
}
.sidebar {
grid-column: 1;
}
.content {
grid-column: 2;
}

Separation of source and display

Flexbox
The flex-direction property
can take a value of row to
display things as a row or
column to display them as
a column.
nav ul{
display: flex;
justify-content: space-between;
flex-direction: row;
}

Flexbox
The visual order can be
switched using row-
reverse or column-reverse.
nav ul{
display: flex;
flex-direction: row-reverse;
}

Flexbox
Adding display: flex to our
container element causes
the items to display flexibly
in a row.
.wrapper {
display: flex;
}

Flexbox
The order property means
we can change the order of
flex items using CSS.
This does not change their
source order.
li:nth-child(1) {
order: 3;
}
li:nth-child(2) {
order: 1;
}
li:nth-child(3) {
order: 4;
}
li:nth-child(4) {
order: 2;
}

Grid Layout
I have created a grid on
my wrapper element.
The grid has 3 equal
width columns.
Rows will be created as
required as we position
items into them.
.wrapper {
display: grid;
grid-template-columns: 1fr 1fr 1fr;
}

Grid Layout
I am positioning my
elements using CSS Grid
Layout line-based
positioning.
Setting a column and a
row line using the grid-
column and grid-row
properties.
li:nth-child(1) {
grid-column: 3 / 4 ;
grid-row: 2 / 3;
}
li:nth-child(2) {
grid-column: 1 / 2;
grid-row: 2 / 3;
}
li:nth-child(3) {
grid-column: 1 / 2;
grid-row: 1 / 2;
}
li:nth-child(4) {
grid-column: 2 / 3;
grid-row: 1 / 2;
}

ConFoo 2016: Making Sense of CSS Layout

CSS Grid automatic placement
http://www.w3.org/TR/2015/WD-css-grid-1-20150917/#grid-auto-
flow-property
https://rachelandrew.co.uk/archives/2015/04/14/grid-layout-
automatic-placement-and-packing-modes/

Grid Layout
When using automatic
placement we can create
rules for items in our
document - for example
displaying portrait and
landscape images
differently.
.wrapper {
display: grid;
grid-template-columns: 1fr 1fr 1fr 1fr;
grid-template-rows: auto;
}
.landscape {
grid-column-end: span 2;
}

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

Grid Layout
With a dense packing
mode grid will move items
out of source order to
backfill spaces.
.wrapper {
display: grid;
grid-template-columns: 1fr 1fr 1fr 1fr;
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.

With great power comes
responsibility.

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://drafts.csswg.org/css-flexbox/#order-accessibility
Authors must use order only for visual,
not logical, reordering of content. Style
sheets that use order to perform
logical reordering are non-conforming.

https://rachelandrew.co.uk/archives/2015/07/28/modern-css-layout-power-and-responsibility/

CSS Box Alignment Module Level 3
“This module contains the features of CSS relating to the
alignment of boxes within their containers in the various CSS box
layout models: block layout, table layout, flex layout, and grid
layout.” - https://drafts.csswg.org/css-align/

Vertically centre ALL THE THINGS!

Distributed alignment
justify-content and align-content properties.
Values: space-between, space-around, stretch, space-evenly

Flexbox
The justify-content
property is set to space-
between.
The items at each end are
placed against the
container and the
remaining space
distributed evenly.
nav ul{
display: flex;
}

Flexbox
The justify-content
property is set to space-
around.
The items are evenly
distributed in the container
with a half size space at
each end.
nav ul{
display: flex;
justify-content: space-around;
}

Default alignment
Used by the justify-items and align-items properties.
The align-items and justify-items properties set the default align-
self and justify-self behavior of the items contained by the
element.

Flexbox
The value of align-items is
stretch by default.
If I add extra text in one
navigation point the others
all take the same height.
nav ul{
display: flex;
align-items: stretch;
}

Flexbox
If I set the value of align-
items to center then we
get vertical centring.
nav ul{
display: flex;
align-items: center;
}

Flexbox
If flex-direction is column
and I set the value of align-
items to center then we
get horizontal centring.
nav ul{
display: flex;
flex-direction: column;
}

Self alignment
justify-self and align-self properties.
The justify-self and align-self properties control alignment of the
box within its containing block.

Flexbox
You can use the align-self
and justify-self properties
to target individual flex
items.
In this example I have set
the group to centre, but
the third item to stretch.
nav ul{
display: flex;
}
nav li:nth-child(3) {
align-self: stretch;
}

Box alignment in CSS Grid Layout

Grid Layout
Creating a grid with the
align-items property set
to centre.
All items will be centered
inside their grid area.
.wrapper {
display: grid;
grid-template-columns: repeat(5, 150px 10px) 150px;
grid-template-rows: 150px 10px 150px 10px 150px 10px 150px;
}
.a {
grid-column: 1 / 4;
grid-row: 1 / 4;
}
.b {
grid-column: 5 / 8;
grid-row: 1 / 4;
}
.c {
grid-column: 1 / 4;
grid-row: 5 / 10;
}
.d {
grid-column: 5 / 8;
grid-row: 5 / 10;
}
.e {
grid-column: 9 / 12;
grid-row: 1 / 10;
}

http://gridbyexample.com/examples/#example24

Grid Layout
Creating a grid with the
justify-items property set
to centre.
All items will be centered
horizontally inside their
grid area.
.wrapper {
display: grid;
justify-items: center;
grid-template-columns: repeat(5, 150px 10px) 150px;
grid-template-rows: 150px 10px 150px 10px 150px 10px
150px;
}
.a {
grid-column: 1 / 4;
grid-row: 1 / 4;
}
.b {
grid-column: 5 / 8;
grid-row: 1 / 4;
}
.c {
grid-column: 1 / 4;
grid-row: 5 / 10;
}
.d {
grid-column: 5 / 8;
grid-row: 5 / 10;
}
.e {
grid-row: 1 / 10;
}

Grid Layout
As with flexbox we can
use align-self and justify-
self to target individual
grid items.
.a {
grid-column: 1 / 4;
grid-row: 1 / 4;
align-self: stretch;
}
.b {
grid-column: 5 / 8;
grid-row: 1 / 4;
align-self: end;
}
.c {
grid-column: 1 / 4;
grid-row: 5 / 10;
align-self: start;
}
.d {
grid-column: 5 / 8;
grid-row: 5 / 10;
align-self: center;
}
.e {
grid-row: 1 / 10;
}

Ethan Marcotte, Fluid Grids
“… every aspect of the grid—and the
elements laid upon it—can be
expressed as a proportion relative to
its container.”

target ÷ context = result
h1 {
margin-left: 14.575%; /* 144px / 988px = 0.14575 */
width: 70.85%; /* 700px / 988px = 0.7085 */
}

Flexbox
The most simple flexbox
example demonstrates
the inherent flexibility.
The items will be
displayed as a row, with
equal space between each
item.
nav ul{
display: flex;
}

The flex property
• flex-grow - add space
• flex-shrink - remove space
• flex-basis - the initial size before any growing or
shrinking

https://drafts.csswg.org/css-flexbox/#flex-components
Authors are encouraged to control
flexibility using the flex shorthand rather
than with its longhand properties
directly, as the shorthand correctly
resets any unspecified components to
accommodate common uses.

Flexbox
flex: 1 1 200px;
flex-grow: 1
flex-shrink: 1;
flex-basis: 200px;
The initial width of our
box is 200 pixels,
however it can grow
larger and shrink smaller
than 200 pixels.
.boxes {
display: flex;
}
.box {
flex: 1 1 200px;
min-width: 1px;
}

Flexbox
flex: 1 1 200px;
flex-grow: 1
flex-shrink: 1;
flex-basis: 200px;
If we allow the flex items
to wrap we can see how
flex-basis works by
dragging the window
smaller.
.boxes {
display: flex;
flex-flow: row wrap;
}
.box {
flex: 1 1 200px;
min-width: 1px;
}

Flexbox
flex: 0 1 200px;
flex-grow: 0
flex-shrink: 1;
flex-basis: 200px;
The initial width of our
box is 200 pixels, it can
shrink smaller than 200
pixels but may not get
larger.
.boxes {
display: flex;
}
.box {
flex: 0 1 200px;
min-width: 1px;
}

Flexbox
flex: 1 1 200px;
flex-grow: 1;
flex-shrink: 1;
flex-basis: 200px;
.box3 has been set to
flex: 0 1 200px;
so cannot grow.
.boxes {
display: flex;
}
.box {
flex: 1 1 200px;
min-width: 1px;
}
.box3 {
flex: 0 1 200px;
}

Flexbox
If we set box3 to 
flex-grow: 2
This box will be assigned
twice of much of the
available free space after
we have reached the 200
pixel initial width.
.boxes {
display: flex;
}
.box {
flex: 1 1 200px;
min-width: 1px;
}
.box3 {
2 1 200px;
}

http://madebymike.com.au/demos/flexbox-tester/

Grid Layout
I am creating three grid
column tracks, all 1fr in
width.
This gives me three equally
sized column tracks.
.wrapper {
display: grid;
grid-template-columns: 1fr 1fr 1fr;
}

Grid Layout
If I create the first column
as 600 pixels and then
have two 1fr columns the
600 pixel track is removed
from the available space
and the remainder is
distributed equally
between the two columns.
.wrapper {
display: grid;
grid-template-columns: 600px 1fr 1fr;
}

Grid Layout
With a 600 pixel column, a
1fr and a 3fr column. The
600 pixels is removed from
the available space then
the remaining space is
divided by 4.
The 1fr column gets 25%
and the 3fr column 75%.
.wrapper {
display: grid;
grid-template-columns: 600px 1fr 3fr;
}

http://alistapart.com/article/holygrail
Three columns. One fixed-width
sidebar for your navigation, another
for, say, your Google Ads or your Flickr
photos—and, as in a fancy truffle, a
liquid center for the real substance.

Grid Layout
CSS Grid “Holy Grail”
using grid-template-
areas.
//css
.header { grid-area: header;}
.footer { grid-area: footer;}
.side1 { grid-area: nav;}
.side2 { grid-area: ads;}
.content { grid-area: content;}
.wrapper {
display: grid;
grid-template-columns: 300px 20px 1fr 20px 300px;
grid-template-areas:
"header header header header header"
"nav ...... content ...... ads"
"footer footer footer footer footer"
;
}
//html
<div class="wrapper">
<header class="header">This is the header</header>
<article class="content"></article>
<div class="side1"></div>
<div class="side2"></div>
<footer class="footer"></div>
</div>

CSS Anthology, 2004
Q. Is it a bad thing to use effects that
don’t work in some browsers?

2004 Rachel
“Users [of IE] might see square corners
instead of rounded ones […] but they’ll
be able to use the site just as well as
their Mozilla-wielding counterparts.”

It’s one thing to have no rounded
corners. Quite another to have no
layout in an older browser.

http://positioniseverything.net/explorer.html

We need to think about feature
support differently in a world of
evergreen browsers.

Evergreen browsers mean we can
enhance with newer techniques.
Over time our users see the site
incrementally improve.

CSS Grid Layout
• Early implementation in IE10, 11 and current Edge
• Implementation of most of the current spec
behind a flag in Blink
• Prefixed in Webkit Nightlies
• Partial implementation in Firefox Nightlies
• Edge have updating to current spec as ‘High
Priority’ on the backlog

Start with small UI elements
• Your layout doesn’t have to be all flexbox or
nothing.
• Build your layout using the methods that work
for your audience profile.
• Finesse using more modern methods

Grid Layout
Display a dl in two
columns using Grid.
dt elements alway start
on the left, dd on the
right.
@media (min-width: 550px) {
.grid-dl {
display: grid;
grid-template-columns: 1fr 1fr;
}
.grid-dl dt {
grid-column-start: 1;
}
.grid-dl dd {
grid-column-start: 2;
}
.grid-dl dt+dd {
border-top: 2px solid #ccc;
}
}

http://codepen.io/rachelandrew/pen/wKgePy

Flexbox in the real world
Zoe M. Gillenwater - Enhancing Responsiveness With Flexbox
https://www.youtube.com/watch?v=_98SE8WUvLk

Check your stats before making
assumptions about support.

Separate desktop and mobile
statistics - your mobile users may
well have far more capability.

Use modern methods for
prototyping and benefit from rapid
design in the browser.

Take an interest in early stage
specifications in order to feed back
to the process. Have your say.

Thank you
Slides & Resources:  
https://rachelandrew.co.uk/presentations/modern-css-layout
http://csslayout.news - sign up for my weekly CSS Layout email
—
@rachelandrew
me@rachelandrew.co.uk
—
https://rachelandrew.co.uk
https://grabaperch.com

ConFoo 2016: Making Sense of CSS Layout

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