A collection of mistakes I've made in my CSS, how I fixed them, and how trying and failing has made me better.

1. CSS Lessons Learned the Hard Way
Zoe Mickley Gillenwater
@zomigi
Beyond Tellerand
Berlin 4 November 2014

2. I make things…

3. …some of which come out nicely…

4. Web sites

5. 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

6. Kids

7. Cakes

8. …but sometimes I make mistakes…

9. Gardening

10. Gardening
https://www.flickr.com/photos/coachjeff/3600883487/

12. “I can’t start until I know enough to do it perfectly.”

13. You don’t need everything
http://www.flickr.com/photos/montage_man/4713541238/

14. Start using Sass in four easy steps.

15. Install Prepros from http://alphapixels.com/prepros/
Step 1

16. Drag your web site’s folder into Prepros.
Step 2

17. In this folder, create a file named styles.scss.
Step 3

18. 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;
}

19. Never compare your inside with somebody else’s outside.

20. 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

21. 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

22. 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

23. Creative people experiment a lot more, therefore succeed a lot more, therefore fail a lot more.

24. Some of my recent CSS mistakes

25. Flexbox demo
www.smoresday.us
Use Chrome, Opera, Safari 7, Firefox 28+, or IE 10+ for full effect

26. .action
.component

27. 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>

28. HTML for flexbox version
<form class="builder">
<section class="component">
<section class="component">
<section class="component">
<section class="component">
<section class="action">
</form>

29. Allow boxes to wrap
.builder {
display: flex;
flex-wrap: wrap;
justify-content: space-between;
margin: 0 0 40px -20px;
}

30. Using flex to control width/height
.flex-item {
flex: 1 0 100px;
}
flex-grow
flex-shrink
flex-basis

31. 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)

32. 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.”

33. Flexbox fail

34. This fixed it
.component {
flex: 1;
margin-right: 1px;
}

35. /* this is needed to make .action wrap to second line. why??? */
My comment on the 1px margin

36. 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.

37. 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.

38. 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.).

39. This was not just a case of succeeding despite a mistake. It was a case of succeeding because of a mistake.

40. flex-basis mistake round two

41. 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;

42. Trying to make one twice as wide
.gallery-item {
flex: 1 0 200px;
}
.feature {
flex: 2 0 200px;
}

43. Expected rendering

44. Actual rendering

45. 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;

46. 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

47. It’s because flex-basis = 200px

48. I really get flex-basis now

49. Takeaway: don’t use CSS shorthand without understanding all the pieces

50. Let’s talk about another mistake

51. Shadow style inspiration
http://sliderpro.net/examples/minimal-slider/

52. The plan: create shadow with generated content, skew it with CSS perspective

55. 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);
}

56. Perspective fail

58. What does rotateX actually do?

59. 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/

60. Or, if your hand is effed up:
http://architecture.gtu.ge/MPL/Multimodal%20Explorer/Acad_11/14control_workplane0/control_workplane.htm

61. 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/

62. My quick sketch

63. 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);
}

64. Perspective working

65. Takeaway: sometimes pen and paper can make a new concept real to you

66. A two-dimensional problem

67. Absolute positioning

68. https://www.flickr.com/photos/40325561@N04/8176648959/
Web layout is horizontally biased

69. Flexbox is not row-centric
.container {
display: flex;
flex-direction: column-reverse;
align-items: flex-start;
min-height: 200px;
}

70. Correct
IE 11 min-height bug

71. Fixed with another flex wrapper
<div class="outer">
<div class="container">
<div class="bottom">...</div>
</div>
</div>
.outer {
display: flex;
}

72. Takeaway: thinking about web layout in rows can be limiting

73. Is using flexbox another one of my mistakes?

74. Flexbox fallback #1: Do nothing. (Seriously.)

75. Flexbox fallback #2: display: table-cell

76. Flexbox fallback #3: float (but be careful)

77. Flexbox with float
.container {
display: -webkit-box;
display: flex;
}
.sidebar {
float: left;
position: relative;
width: 300px;
}
.no-flexbox .main-content {
margin-left: 300px;
}

78. Flexbox fallback example
Without flexbox (IE 9)
With flexbox (Chrome)

79. 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;
}

80. A more public mistake

81. Sometimes you need to add special content for screen reader users…

83. …and occasionally you need to hide content from screen reader users.

85. 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

86. Hide content visually and aurally
.hidden-silent {
display: none;
visibility: hidden;
}

87. Hide text only but keep it spoken
.hidden-text-spoken {
text-indent: -999em;
overflow: hidden;
display: inline-block;
}

88. 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

89. Problem: NVDA in Firefox wouldn’t read <label> with this class

90. https://www.flickr.com/photos/87255087@N00/6261885005/
Delete half the code, see if bug goes away, repeat

91. I narrowed it down to overflow: hidden
Removing this part caused labels to be read correctly in Firefox by NVDA

92. But removing it still kept the content hidden.
So why was it there to begin with?

96. This scrollbar is what overflow fixes

97. Now that I understood what overflow did, I could decide if I needed it.

98. 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

99. (By the way, this FF/NVDA bug seems to be gone now.)

100. Takeaway: one-size-fits-all isn’t always best for your needs

101. Takeaway: you can get help when you share your confusion publicly

102. Be willing to fail…

103. …and then tell us about it.

104. 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

105. Sharing mistakes has benefits

106. http://www.flickr.com/photos/stilleben/49644790/

107. We all do imperfect work

108. /* this is needed to make .action wrap to second line. why??? */

109. 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.

110. Revisiting comments
// TODO: Fix this. Fix what?
// somedev1 - 6/7/02 Adding temporary tracking of Login screen // somedev2 - 5/22/07 Temporary my ass

112. 99% of the population of the world doesn’t know CSS.
Zoe’s made-up statistic

113. You are awesome, but and you make mistakes.

114. Let’s use our confidence in our skills to build others up and bravely admit our own shortcomings.

115. Thank you
Zoe Mickley Gillenwater
@zomigi
Beyond Tellerand
Berlin 4 November 2014