[!]
[=title "Week 11: Flexbox 2"]
[=content-]
<p>
	If you haven't already, read <a href="week-8-flexbox-1.html">Flexbox 1</a>.
</p>
<p>
	To complete our discussion of flexbox, we need to talk first about <i>axes</i>. The core idea is that a flexbox is
	an <i>axis</i>: it puts content vertically or horizontally. It <i>can</i> violate this with <code>flex-wrap</code>,
	but please don't do that. We say the axis along which content is distributed is the <b>primary axis</b>:
	for default flexboxes, this is left/right (horizontal), but they can also be up/down (vertical).
</p>
<p>
	You control the <i>primary</i> axis with the <code>flex-direction</code> property.
	<code>flex-direction: row;</code> will set the flexbox' primary axis to horizontal,
	and <code>flex-direction: column;</code> will set the flexbox' primary axis to vertical.
	The <i>secondary axis</i> will always be the remaining option.
</p>
<p>
	Along the secondary axis (up/down for a horizontal flexbox, left/right for a vertical flexbox), elements
	may be centered, stretched, or justified to either end: you do this with the <code>align-items</code>
	property. For instance, <code>align-items: center;</code> will bring all of the elements
	to the center of the secondary axis. This is pretty useful for building centered layouts! 
</p>
<p>
	Using <code>align-items: center; justify-content: center;</code> centers along both axes (remember, <code>justify-content</code> controls
	the primary axis!), so for example:
</p>
<div style="border: 1px dashed white;display:flex;align-items:center;justify-content:center;height:200px;">
<div style="background-color: red;">Content 1</div>
<div style="background-color: blue;">Content 2</div>
</div>
<p>
	Note that we can also force elements to stretch to fill up the secondary axis with
	<code>align-items: stretch;</code>:
</p>
<div style="border: 1px dashed white;display:flex;align-items:stretch;justify-content:center;height:200px;">
<div style="background-color: red;">Content 1</div>
<div style="background-color: blue;">Content 2</div>
</div>
<p>
	What if we want to mix the two? It turns out that we can do that with the
	<code>align-self</code> property! Note that there is no <code>justify-self</code> property;
	<code>align-self</code> works because of the assumption that there is only one element
	at any point on the secondary axis (an assumption violated by <code>flex-wrap</code>, but we won't talk about that here).
	If we do <code>align-self: center;</code> for the first element...
</p>
<div style="border: 1px dashed white;display:flex;align-items:stretch;justify-content:center;height:200px;">
<div style="background-color: red;align-self: center;">Content 1</div>
<div style="background-color: blue;">Content 2</div>
</div>
<p>
	All three properties also support two strange values: <code>start</code> and <code>end</code>.
	Doing <code>justify-content: end;</code> on the flexbox and <code>align-self: start;</code> on
	the second content: 
</p>
<div style="border: 1px dashed white;display:flex;align-items:stretch;justify-content:end;height:200px;">
<div style="background-color: red;align-self: center;">Content 1</div>
<div style="background-color: blue;align-self: start;">Content 2</div>
</div>
<p>
	Strange! <code>end</code> simply means "the furthest point across the axis" - which is usually
	as far right (or as far down) as possible. <code>start</code> just means the opposite.
</p>
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