Post on 29-Jun-2015
description
CSS Lessons Learned the Hard Way
Zoe Mickley Gillenwater @zomigi
Beyond Tellerand
Berlin 4 November 2014
I make things…
…some of which come out nicely…
Web sites
Books
Stunning CSS3: A Project-based Guide
to the Latest in CSS
www.stunningcss3.com
Flexible Web Design: Creating Liquid and Elastic
Layouts with CSS
www.flexiblewebbook.com
Kids
Cakes
…but sometimes I make mistakes…
Gardening
Gardening
https://www.flickr.com/photos/coachjeff/3600883487/
“I can’t start until I know enough to do it perfectly.”
You don’t need everything
http://www.flickr.com/photos/montage_man/4713541238/
Start using Sass in four easy steps.
Drag your web site’s folder into Prepros.
Step 2
In this folder, create a file named styles.scss.
Step 3
Write in it this:
Step 4
$green: #4F9F1A; $blue: #1D6783; $lightgray: #D6D6D6; body { background: $lightgray; color: $green; } a { color: $blue; } button { background: $blue; color: $lightgray; }
Never compare your inside with somebody else’s outside.
If you walk around with the idea that there are some people
who are so gifted—they have these wonderful things in their head,
but you’re not one of them, you’re just sort of a normal person,
you could never do anything like that— then you live a different kind of life.
Brian Eno
Innovation requires a mindset that rejects the
fear of failure and replaces that fear of failure with the
joy of exploration and experimental learning.
Dr. Edward D. Hess
We also need to accept and embrace the concept of failure, not because failure is a good thing but
because it’s a natural part of the path of progress.
If you’re failing, at least that means you’re trying — not remaining on the outside of the arena, looking in.
Helen Walters
Creative people experiment a lot more,
therefore succeed a lot more, therefore fail a lot more.
Some of my recent CSS mistakes
Flexbox demo www.smoresday.us Use Chrome, Opera, Safari 7, Firefox 28+, or IE 10+ for full effect
.action
.component
HTML without flexbox <form class="builder">
<div class="wrap">
<section class="component">
<section class="component">
<section class="component">
<section class="component">
</div>
<section class="action">
</form>
HTML for flexbox version
<form class="builder">
<section class="component">
<section class="component">
<section class="component">
<section class="component">
<section class="action">
</form>
Allow boxes to wrap
.builder {
display: flex;
flex-wrap: wrap;
justify-content: space-between;
margin: 0 0 40px -20px;
}
Using flex to control width/height
.flex-item {
flex: 1 0 100px;
}
flex-grow flex-shrink flex-basis
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)
My first attempt
.component {
flex: 1;
}
.action {
flex: 1 1 100%;
}
Zoe’s Brain Said: “Since .action starts out at 100%, it won’t have space to sit on the first line with the content preceding it, and will wrap to a second line.”
Flexbox fail
This fixed it
.component {
flex: 1;
margin-right: 1px;
}
/* this is needed to
make .action wrap to
second line. why??? */
My comment on the 1px margin
The hidden flex-basis value
.component {
flex: 1 1 0px;
}
.action {
flex: 1 1 100%;
}
Reality: Since it’s fine for each .component to shrink to only 0px wide, a 100% wide element can and will sit on the same line as all the components.
That’s why margin “fixed” it
.component {
flex: 1;
margin-right: 1px;
}
.action {
flex: 1 1 100%;
}
What’s happening: Now each .component starts out taking up 1px of space, so a 100% wide element can’t and won’t sit on the same line with any of the components.
Fixing flex-basis to force the wrap
.component {
flex: 1 1 200px;
}
.action {
flex: 1 1 100%;
}
Fixed: .action will always wrap to new line, and .component boxes will wrap to additional lines when there’s less space than their combined flex-basis values (plus margin, etc.).
This was not just a case of succeeding despite a mistake.
It was a case of succeeding because of a mistake.
flex-basis mistake round two
flex can be proportional
Setting flex-grow/flex-shrink to different values can make flex items size
themselves relative to each other
flex: 1; flex: 1; flex: 2;
Trying to make one twice as wide
.gallery-item {
flex: 1 0 200px;
}
.feature {
flex: 2 0 200px;
}
Expected rendering
Actual rendering
What I figured out
Having widths be in multiples of each other only works if flex-basis is 0
flex: 1 0 0px; flex: 1 0 0px; flex: 2 0 0px;
If flex-basis isn’t 0px…
…the widths may not end up as you expect
The third box gets twice as much of the extra, but that doesn’t make it twice as
wide overall
flex: 1 0 10px; flex: 1 0 10px; flex: 2 0 10px;
10px + 5px extra = 15px 10px + 5px extra = 15px 10px + 10px extra = 20px
if 50px available
It’s because flex-basis = 200px
I really get flex-basis now
Takeaway: don’t use CSS shorthand without understanding
all the pieces
Let’s talk about another mistake
Shadow style inspiration
http://sliderpro.net/examples/minimal-slider/
The plan: create shadow with generated content,
skew it with CSS perspective
My first attempt .lightbox:before {
content: "";
position: absolute;
z-index: -2;
left: 2%;
bottom: 0;
width: 96%;
height: 1px;
box-shadow: 0 25px 30px 15px hsla(0,0%,0%,.4);
transform: perspective(20em);
}
Perspective fail
What does rotateX actually do?
The 3 axes
X horizontal, left-right
Y vertical, up-down
Z away-towards you
A helpful diagram: your hand. Photo: http://www.smashingmagazine.com/2012/01/06/adventures-in-the-third-dimension-css-3-d-transforms/
Or, if your hand is effed up:
http://architecture.gtu.ge/MPL/Multimodal%20Explorer/Acad_11/14control_workplane0/control_workplane.htm
Rotate around the axis not in the direction of the axis
As explained well by Peter Gasston in http://www.smashingmagazine.com/2012/01/06/adventures-
in-the-third-dimension-css-3-d-transforms/
My quick sketch
Adding rotateX with perspective .lightbox:before {
content: "";
position: absolute;
z-index: -2;
left: 6%;
bottom: 0;
width: 88%;
height: 1px;
box-shadow: 0 25px 30px 15px hsla(0,0%,0%,.4);
transform: perspective(20em) rotateX(50deg);
}
Perspective working
Takeaway: sometimes pen and paper can make a new concept
real to you
A two-dimensional problem
Absolute positioning
https://www.flickr.com/photos/40325561@N04/8176648959/
Web layout is horizontally biased
Flexbox is not row-centric
.container {
display: flex;
flex-direction: column-reverse;
align-items: flex-start;
min-height: 200px;
}
Correct
IE 11 min-height bug
Fixed with another flex wrapper
<div class="outer">
<div class="container">
<div class="bottom">...</div>
</div>
</div>
.outer {
display: flex;
}
Takeaway: thinking about web layout in
rows can be limiting
Is using flexbox another one of my mistakes?
Flexbox fallback #1: Do nothing. (Seriously.)
Flexbox fallback #2: display: table-cell
Flexbox fallback #3: float
(but be careful)
Flexbox with float .container { display: -webkit-box; display: flex; } .sidebar { float: left; position: relative; width: 300px; } .no-flexbox .main-content { margin-left: 300px; }
Flexbox fallback example
Without flexbox (IE 9) With flexbox (Chrome)
Flexbox with float fallback .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; }
A more public mistake
Sometimes you need to add special content for
screen reader users…
…and occasionally you need to hide content from
screen reader users.
I needed CSS classes to:
1. Hide content visually and aurally 2. Hide just the text of an element, not
whole element, but keep text spoken 3. Hide whole element visually but keep
its text spoken by screen readers
Hide content visually and aurally
.hidden-silent {
display: none;
visibility: hidden;
}
Hide text only but keep it spoken
.hidden-text-spoken {
text-indent: -999em;
overflow: hidden;
display: inline-block;
}
Hide element but keep it spoken
Yahoo! Accessibility blog said to use:
.hidden-spoken {
position: absolute !important;
clip: rect(1px 1px 1px 1px); /* IE 6-7 */
clip: rect(1px, 1px, 1px, 1px);
padding: 0 !important;
border: 0 !important;
height: 1px !important;
width: 1px !important;
overflow: hidden;
}
Article now online at https://developer.yahoo.com/blogs/ydn/clip-hidden-content-better-accessibility-53456.html
Problem: NVDA in Firefox wouldn’t read <label> with this class
https://www.flickr.com/photos/87255087@N00/6261885005/
Delete half the code, see if bug goes away,
repeat
I narrowed it down to overflow: hidden
Removing this part caused labels to be read correctly in Firefox by NVDA
But removing it still kept the content hidden.
So why was it there to begin with?
This scrollbar is what overflow fixes
Now that I understood what overflow did, I could
decide if I needed it.
How I fixed my mistake
• Removed overflow:hidden from new instances going forward (but sadly not fixed in existing style sheets)
• Updated documentation to advise adding it on as-needed basis
(By the way, this FF/NVDA bug seems to be gone now.)
Takeaway: one-size-fits-all isn’t always
best for your needs
Takeaway: you can get help when you
share your confusion publicly
Be willing to fail…
…and then tell us about it.
Vulnerability is the birthplace of innovation, creativity, and change.
To create is to make something that has never existed before.
There's nothing more vulnerable than that.
Dr. Brené Brown
Sharing mistakes has benefits
http://www.flickr.com/photos/stilleben/49644790/
We all do imperfect work
/* this is needed to
make .action wrap to
second line. why??? */
The evidence in the comments
// Dear future me. Please forgive me. // I can't even begin to express how sorry I am.
// I am not sure if we need this, but too scared to delete.
// Magic. Do not touch.
Revisiting comments
// TODO: Fix this. Fix what?
// somedev1 - 6/7/02 Adding temporary tracking of Login screen // somedev2 - 5/22/07 Temporary my ass
99% of the population of the world doesn’t know CSS.
Zoe’s made-up statistic
You are awesome, but and you make mistakes.
Let’s use our confidence in our skills to build others up and bravely admit our own
shortcomings.
Thank you
Zoe Mickley Gillenwater @zomigi
Beyond Tellerand
Berlin 4 November 2014