Trouble aligning items with flexbox [duplicate] - css

Question

This question already has an answer here:
Remove space (gaps) between multiple lines of flex items when they wrap
(1 answer)
Closed 4 years ago.
enter code hereI can't really explain it better than this code example.
https://codepen.io/anon/pen/BYeger
I want to make #thing_down_here touch #thing_up_here, but I can't figure out the right combination.
html, body {
margin: 0;
padding: 0;
}
* {
box-sizing: border-box
}
#parent {
width: 100vw;
height: 100vh;
background: cornsilk;
display: flex;
flex-wrap: wrap;
justify-content: center;
}
#thing_up_here {
flex: 1 0 100%;
background: skyblue;
height: 80px;
}
#thing_down_here {
flex: 0 0 50%;
background: lightgreen;
height: 100px;
}
<div id="parent">
<div id="thing_up_here"></div>
<div id="thing_down_here"></div>
</div>

Answer 1

You need to use use the align-content property to set the distribution along the cross-axis.
html, body {
margin: 0;
padding: 0;
}
* {
box-sizing: border-box
}
#parent {
width: 100vw;
height: 100vh;
background: cornsilk;
display: flex;
flex-wrap: wrap;
justify-content: center;
align-content: flex-start;
}
#thing_up_here {
flex: 1 0 100%;
background: skyblue;
height: 80px;
}
#thing_down_here {
flex: 0 0 50%;
background: lightgreen;
height: 100px;
}
<div id="parent">
<div id="thing_up_here"></div>
<div id="thing_down_here"></div>
</div>
Read more about align-content.

Answer 2

Add align-content: flex-start to #parent
This defines the default behaviour for how flex items are laid out along the cross axis on the current line. Think of it as the justify-content version for the cross-axis (perpendicular to the main-axis).
flex-start: cross-start margin edge of the items is placed on the cross-start line
The default is stretch which is causing your issue
More on it at https://css-tricks.com/snippets/css/a-guide-to-flexbox/
html, body {
margin: 0;
padding: 0;
}
* {
box-sizing: border-box
}
#parent {
width: 100vw;
height: 100vh;
background: cornsilk;
display: flex;
flex-wrap: wrap;
justify-content: center;
align-content: flex-start;
}
#thing_up_here {
flex: 1 0 100%;
background: skyblue;
height: 80px;
}
#thing_down_here {
flex: 0 0 50%;
background: lightgreen;
height: 100px;
}
<div id="parent">
<div id="thing_up_here"></div>
<div id="thing_down_here"></div>
</div>