CSS Properties & Flexbox
Joel Ross
Autumn 2023
View of the Day
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Admin Stuff
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Q & A (PollEv)
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CSS Properties (lecture, PollEv)
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Fonts
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Layouts
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Flexbox Demo (code together!)
START WORKING ON
PROBLEM SET 03 EARLY!
It's a bigger problem set (3 problems!) and will take you longer than the previous one. Don't put it off and fall behind! Start tonight if you haven't yet!
Updating Lecture Code
# switch to starter branch to get new starter code
git checkout starter
# download new starter code
git pull
# switch back to main branch for coding
git checkout main
# merge in new starter code (use default msg)
git merge starter --no-edit
# code and enjoy!Get the starter code from the starter branch, but do all of your work on main.
Q&A
Fonts
Fonts are installed "per computer", so not every computer has the same fonts (which is why you set a default with font-family).
Fonts are installed "per computer", so not every computer has the same fonts (which is why you set a default with font-family).
p {
font-family: 'Helvetica', 'Arial', sans-serif;
}Use this font
If first isn't available,
use this
If nothing else,
use this style of font-face
Generic Fonts
All fonts are categories in 1 of 5 different "categories", each of which has a generic style.
Serif vs. Sans-Serif
Research (roughly) suggests that sans-serif fonts are easier to read on screens, as well as more accessible for users with e.g., dyslexia.
Font Units
All browsers have a "default" font size--generally 16px. We use relative font sizing in case of variations.
Note that units are "measurement units" (think: inches)
| em | relative to the parent font size | By default 2em = 32px But if the parent's font-size was 20px, then 2em = 40px |
| rem | relative to the root (body's) font size of 16px | 2rem = 32px usually |
| % | relative to parent font size or dimension, can use for width or height | if parent width is 300px, then 50% = 150px |
| px | absolute measurement (do not use for fonts) | 16px = 16px |
It is also possible to specify an online font that the browser will download and display.
Fonts
Fonts are installed "per computer", so not every computer has the same fonts (which is why you set a default with font-family).
Fonts are installed "per computer", so not every computer has the same fonts (which is why you set a default with font-family).
p {
font-family: 'Helvetica', 'Arial', sans-serif;
}Use this font
If first isn't available,
use this
If nothing else,
use this style of font-face
Style & Weight
You can make a font italics using the font-style property, or bold using the font-weight property. Font weights are measured in different ordinal values (e.g., there is no "549" value for weight).
Note that italic and bold versions of fonts are technically different typefaces (and need to be installed separately)
Box Model
All HTML elements take up space on a page based on their "box size". You can manipulate the box model to change the size and appearance of the element
<div class="cow">
<p>Moo moo moo.</p>
<p>Moooooooooooooooooooo.</p>
</div>
<div class="sheep">
<p>Baa baa <span class="dark">black</span> sheep,
have you any wool?</p>
</div>
block element (line break after)
inline element
Block and Inline
All HTML elements are either block elements (default box takes up the width of the page, and is followed by a "line break") or inline elements (default box takes up the size of the content, and is inline with other text).
Display Property
You can customize whether an element is displayed as a block or inline element using the display property.
Choose elements based on their semantics, not their appearance!
/* <li> elements will be inline (an inline list!) */
li {
display: inline;
}display: inline-block
You cannot set the width or height of an inline element, but you can adjust the size of an inline-block element.
Position
You can use the position property to adjust where an element appears on the page from its normal layout. You will also need to set position adjustment values top, left, bottom, and/or right
/* position element 20px up and to the right
* of where it "normally" would be */
img.badge {
position: relative;
top: 20px;
right: 20px;
}LIMIT USE OF THE
position AND float
PROPERTIES!
Flexbox
A flexbox is an element that allows you to flexibly customize the layout of its children.
An element is made into a flexbox by giving it the display: flex CSS property.
flexbox
child elements
Flexbox Properties
Customize the layout of the flexbox's children by given the flexbox additional CSS properties. For example:
flex-wrap
justify-content
Child Properties
You can also customize the children of the flexbox (the elements that are inside the box) by giving them additional CSS properties. For example:
flex-grow
Flexbox vs. Children
Don't get the flexbox (sometimes called the flex container) mixed up with the child elements (sometimes called the flex items) that are inside of it!
- The flexbox specifies how its children are positioned.
- The child elements specify how much space they should take up.
Nesting Flexboxes
A flexbox can contain other flexboxes inside of it!
That is: a child of a flexbox can itself be a flexbox (specifying how its children are positioned).
But a flexbox only influences its children, not its grandchildren! A flexbox lays out its child boxes; what happens inside those boxes is their own business.
Using Flexboxes
Flexboxes are great solutions for:
- Centering block elements (use justify-content)
- Creating "columns" for a page"
- Making an element fill a space larger than its content (use flex-grow)
- ... and more!
Flexboxes are not great solutions for:
- Having block elements stack on top of each other (just use normal elements!)
- Adding specific spacing between elements (use margin/padding)
- ... doing anything else that the browser does by default!
Action Items!
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Read: through Chapter 8
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Problem Set 03 due FRIDAY!!
Next: Responsive Design & Media Queries
info340au23-css-flexbox
By Joel Ross
