With solidified syntax and great browser support, flexbox, the CSS layout module that can make your layouts more flexible and responsive with ease, is finally ready to be used in your real-world work. We’ll talk about the when, what, and how of using flexbox today: when it’s a great choice use flexbox (and when not to), what UI and UX problems it can help you solve, and how to add it to your layouts in a robust way that doesn’t harm non-supporting browsers or accessibility. You’ll learn a step-by-step process for deciding on and deploying flexbox, with lots of examples along the way of flexbox in the wild.
8. What browsers do I need to
support?
Don’t ask yourself this—it’s irrelevant here
(IMO)
9. Flexbox has 94% coverage worldwide
We support IE 7-9 at Booking, but still use flexbox as
progressive enhancement.
10. Do I want to create a layout in
1 dimension (row OR column)
or 2 dimensions?
Hat-tip to Rachel Andrew:
https://rachelandrew.co.uk/archives/2016/03/30/should-i-use-grid-or-flexbox/
11. Flexbox is not a grid
Not meant for or great at whole page layout
Flex items only care about space in their
own row/column
They don’t care about lining up in the other
dimension
12. Demo by Rachel Andrew: http://codepen.io/rachelandrew/pen/YqqdXL
13. Flexbox is best for:
UI components
Simple whole page layouts (not grid-based)
Enhancing a complex layout’s alignment,
spacing, etc. (not controlling placement)
14.
15. Do I need my content to dictate
sizing and placement,
or do I need to control these?
16. Content determines
boxes’ size and
placement
(Mega-useful when
content is unknown and
variable, or readability is
a top priority.)
Structure determines
content’s size and
placement
(P.S. Flexbox can do this
too, if you want. It’s just
the reverse that doesn’t
work so well.)
Flexbox Grids
17. Does flexbox offer me anything
I can’t already get
from an existing layout method?
18. New things flexbox offers
Content-driven, unit-less sizes
Content-driven, media-query-less layout changes
Mixed-unit layouts
Equal-height columns
Vertical centering and other alignments
Spacing out or stretching items to fill unknown width/height
Combining content wrapping and block wrapping
Pinning items without overlaps
Visual order different than HTML/reading order
26. My copy of that form
Same floats, same percentage widths
27. The trouble with explicit sizing
Since the select and button are sized by a
percentage, not sized automatically by their
content, this can happen:
Box too small for its content Box too big for its content
28. Use the flex property instead
Tells browser starting size (including content
size) and whether item can grow or shrink
width: 33.333%
flex: auto
Fill up remaining space
width: 16.666%
flex: none
Size to content exactly
29. Form fields are a pain in the butt
The fields and button don’t all match each
other exactly in height
30. Fix alignment with flexbox
Turn each field wrapper into flex container so
field inside will stretch to match height of line:
.flexbox .jobs-form_field-wrapper {
display: flex;
align-items: stretch; /* default */
width: auto;
}
Fields misaligned without flexbox Fields match height due to align-items
35. Defining the flex property
flex-grow
how much flex
item will grow
relative to
other items if
extra space is
available
(proportion
of extra space
that it gets)
flex-shrink
how much item
will shrink
relative to others
if there is not
enough space
(proportion of
overflow that
gets shaved off)
flex-basis
the initial
starting size
before free
space is
distributed
(any standard
width/height
value, including
auto)
36. Translating the flex property
.sb-dates {
display: flex;
}
.sb-dates__icon {
flex: 0 0 23px;
}
.sb-dates__select-day {
flex: 1 0 auto;
margin: 0 6px;
}
.sb-dates__select-month {
flex: 1 1 auto;
}
Start out 23px wide, and don’t grow
or shrink further
Start out sized to your content, then
grow with 1 share of any extra space
available, but don’t ever shrink
Start out sized to your content, then
grow with 1 share of extra space, but
if there’s an overflow shrink
37. Mixed-unit layout is easier with
calc(), but not even it can do:
calc(100% - 23px - the width of
the day field in Greek)
38. Taking advantage of variable space
Task: add a
message about
low availability
of the room
price shown:
“We have only X
left on our site!”
How about right here
in this lovely big gap?
39. Taking advantage of variable space
Problem: the gap
is not always big
enough to hold a
sentence of text
40. Taking advantage of variable space
Solution: use
flexbox to place
text beside price
when space
allows; otherwise,
it can wrap below
price
45. Layout change without media query
1. Let the blocks wrap and stack when needed:
.article-header {
display: flex;
flex-direction: row;
flex-wrap: wrap;
}
/* default */
46. Layout change without media query
2. Size the blocks to control their wrapping
point:
.article-header-image {
flex: 1 1 320px;
padding-left: 20px;
}
.article-header-text {
flex: 1 1 20em;
padding-left: 20px;
}
47. In other words…
Not enough space for
320px + 20em, so text
block wraps. Each block
then stretches wider than
320px/20em to fill its line.
320px + 20em is less than 100%, so both can fit together
on single line. Each then stretch equally as needed to
fill 100% of the space.
48. Stretching to fill unknown width/height
flex: 1 1 auto
align-content:
space-between
49. Improved wrapping in RWD layout
With float or text-align With flex or justify-content
50. Flexbox is great for spacing
and aligning stuff, especially
shifting content in RWD.
51. Demo: full-width nav bar
All links on same line
First link flush left, last link flush right
Equal spaces between all links
52. Trying display:table-cell
All links on same line
First link flush left, last link flush right
Equal spaces between all links
59. Demo: full-height stacked icons
1. Turn children .icons and .content into
side-by-side, equal-height flex items
.wrapper {
display: flex;
align-items: stretch; /* default */
}
60. Only children become flex items
So these 2 children are the flex items
This is the flex container
These 3 grandchildren aren’t flex items (yet)
61. Demo: full-height stacked icons
2. Turn .icons into flex container with
vertically stacked children (the 3 icons):
.icons {
display: flex;
flex-direction: column; /* main axis */
}
62. Demo: full-height stacked icons
3. Equally space the 3 icons along the vertical
main axis:
.icons {
display: flex;
flex-direction: column;
justify-content: space-between;
}
66. Improve the wide layout
Wide: too stretched out
A more responsive enhancement
67. order
integer to specify flow order of flex items
0 0 0default source order 0 0
10 0re-ordered 0 0
0 0-1re-ordered 0 0
210re-ordered 10
68. Use order property to move logo
1. Divide nav bar into order groups:
.list-nav-item_home, .list-nav-item_builder {
order: 0; /* default, and first here */ }
.logo {
order: 1; /* second */ }
.list-nav-item_party, .list-nav-item_tumblr {
order: 2; /* last */ }
69. Use order property to move logo
2. Split extra space on line to center logo:
.logo {
order: 1;
margin-left: auto;
margin-right: auto;
}
71. Order only works on siblings
To move logo to middle of list, it needs to be
part of list
<div class="logo"><img src="images/logo.png"></div>
<ul class="list-nav">
<li class="logo"><img src="images/logo.png"></li>
<li class="link-home"><a>home</a></li>
<li class="link-builder"><a>s'mores builder</a></li>
<li class="link-party"><a>throw a party</a></li>
<li class="link-tumblr"><a>tumblr</a></li>
</ul>
84. Browser support approaches to choose
Use only the non-prefixed, standard syntax
… plus browser-prefixed versions of
standard syntax
… plus -ms- prefixed 2011/2012 syntax
… plus -webkit- prefixed 2009 syntax
85. I recommend you skip the ‘09 syntax
It’s slower to render than current syntax*
Doesn’t support wrapping
Its browsers have small market share
If using flexbox for progressive
enhancement, its browsers can get same
fallback given to non-supporting browsers
* http://updates.html5rocks.com/2013/10/Flexbox-layout-isn-t-slow
86. Let tools add browser variants for you
Autoprefixer: https://github.com/ai/autoprefixer
Sass or LESS mixins can be customized to
add just the browser variants you want
https://github.com/mastastealth/sass-flex-mixin
https://gist.github.com/cimmanon/4461470
https://github.com/thoughtbot/bourbon/blob/mast
er/app/assets/stylesheets/css3/_flex-box.scss
https://github.com/annebosman/FlexboxLess
87. Add Modernizr as needed with flexbox
Flexbox and fallback styles can often co-
exist, but sometimes need to isolate them
http://zomigi.com/blog/using-modernizr-with-flexbox/
88. Or use @supports
.gallery-item {
display: inline-block;
}
@supports (flex-wrap: wrap) {
.gallery {
display: flex;
flex-wrap: wrap;
}
}
https://developer.mozilla.org/en-US/docs/Web/CSS/@supports
But IE 10-11, which do
support flexbox but
don’t support
@supports, won’t get
these styles
90. Things to consider
Do I need content blocks to wrap? not table-cell
Do I want to prevent blocks from wrapping? floats, inline-block, but
table-cell best
Do I need content-driven sizes? floats, but table-cell or
inline-block best
Do I need vertical alignment? inline-block, table-cell
Do I need horizontal alignment? floats, table-cell, inline-
block only with preset
sizes
91. Pick your starter layout CSS
Floats
table-cell
inline-block
Absolute positioning
Flexbox will override: Flexbox will not override:
Just use whatever you normally would;
flexbox plays nicely with most of them.
93. Split left-right layout
Task: lay out review score
and price, on opposite
sides of same line
Needs:
content-driven sizing
horizontal alignment
wrapping
score price or
“sold out”
97. Creating the block flex container
.iw_mini_details_wrapper {
display: flex;
}
.iw_mini_review_score_wrapper {
float: left;
}
.iw_mini_price_wrapper {
float: right;
}
Flex container sits
on a new row below,
like a block element
99. Things to consider
Lay out horizontally or vertically? flex-direction:row or
column
Allow boxes to wrap? flex-wrap:wrap,
wrap-reverse or nowrap
Order different than source? order values;
flex-direction:
row-reverse or
column-reverse
101. Decide which items can
grow to fill space,
shrink to avoid overflow,
or must stay at a certain size
102. Tips for setting flex values
Write out full flex values, rather than
using single-digit and keyword values
flex: 1 1 0% instead of flex: 1
Hidden default values can lead to mistakes
Avoids IE 10-11 bugs
Think about it backwards: first decide
flex-basis, then -shrink, then -grow
103. Tips for setting flex-basis values
Acts like min-width when wrapping on
If flex-wrap off and flex-shrink on,
browser can go smaller than flex-basis
Be careful with flex-basis:0 when
wrapping
Use flex-basis:auto whenever possible
108. Main axis alignment
(horizontal when row,
vertical when column)
Cross axis alignment
(vertical when row,
horizontal when column)
(P.S. Also responsible for
equal-height columns)
justify-content align-items
109. Controlling alignment
.iw_mini_details_wrapper {
display: flex;
flex-wrap: wrap;
justify-content: space-between;
align-items: baseline;
}
.iw_mini_review_score_wrapper {
float: left;
}
.iw_mini_price_wrapper {
float: right;
}
Moves first item to left,
last item to right
113. Testing your flexbox
Too Flexy bookmarklet for toggling
Modernizr flexbox classes:
http://chriswrightdesign.github.io/tooflexy/
If reordering, check tabbing and screen
reading order to make sure it’s still logical
115. Summing up the process
1. Decide whether to use flexbox and which browser
versions of it
2. Choose and add starter layout CSS
3. Choose and add flexbox CSS
1. Block or inline-block container
2. Flow
3. Flex to control sizing
4. Alignment
4. Test and fix bugs
116. Flexbox is not for the future.
You can use flexbox today.