Z-index not working with flex items?
I am trying to have two columns, one of which is a menu that can expand and overlap the other column. But I used a flex item to wrap those columns and my menu expands behind another item, even with a larger one z-index
.
The result looks something like this:
.main {
font-family: 'Open Sans', Helvetica, sans-serif;
display: flex;
background-color: #99baef;
}
nav {
height: 100%;
width: 8em;
background-color: black;
z-index: 1;
}
.navbox {
box-sizing: border-box;
background-color: black;
color: white;
height: 4em;
width: 100%;
text-align: center;
line-height: 4em;
border-top: 1px dotted #99baef;
transition: all 1s;
}
.navbox:hover {
width: 130%;
border-top: none;
background-color: #4a77c4;
color: black;
}
.container {
padding: 1em;
}
a {text-decoration: inherit;}
<div class="main">
<div class="maincolumn">
<nav>
<a href="">
<div class="navbox">
Nav 1
</div>
</a>
<a href="">
<div class="navbox">
Nav 2
</div>
</a>
</nav>
</div>
<div class="maincolumn">
<div class="container">
<h2>Title</h2>
<p>This is a text.</p>
</div>
</div>
</div>
Cm? I want my menu to overlap the rest of my page when expanding. How can i do this?
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The property z-index
only affects elements that have a position value other than static (the default) or that are flex elements (direct children display: flex
or display: inline-flex
).
There are two ways to make it work z-index
in your case:
-
Set
z-index
to 1st.maincolumn
which is a flexbox item:.maincolumn:first-child { z-index: 1; }
.main {
font-family: 'Open Sans', Helvetica, sans-serif;
display: flex;
background-color: #99baef;
}
.maincolumn:first-child {
z-index: 1;
}
nav {
height: 100%;
width: 8em;
background-color: black;
}
.navbox {
box-sizing: border-box;
background-color: black;
color: white;
height: 4em;
width: 100%;
text-align: center;
line-height: 4em;
border-top: 1px dotted #99baef;
transition: all 1s;
}
.navbox:hover {
width: 130%;
border-top: none;
background-color: #4a77c4;
color: black;
}
.container {
padding: 1em;
}
a {text-decoration: inherit;}
<div class="main">
<div class="maincolumn">
<nav>
<a href="">
<div class="navbox">
Nav 1
</div>
</a>
<a href="">
<div class="navbox">
Nav 2
</div>
</a>
</nav>
</div>
<div class="maincolumn">
<div class="container">
<h2>Titre</h2>
<p>This is a text.</p>
</div>
</div>
</div>
or
-
Install
position: relative
innav
:nav { position: relative; height: 100%; width: 8em; background-color: black; z-index: 1; }
.main {
font-family: 'Open Sans', Helvetica, sans-serif;
display: flex;
background-color: #99baef;
}
nav {
position: relative;
height: 100%;
width: 8em;
background-color: black;
z-index: 1;
}
.navbox {
box-sizing: border-box;
background-color: black;
color: white;
height: 4em;
width: 100%;
text-align: center;
line-height: 4em;
border-top: 1px dotted #99baef;
transition: all 1s;
}
.navbox:hover {
width: 130%;
border-top: none;
background-color: #4a77c4;
color: black;
}
.container {
padding: 1em;
}
a {text-decoration: inherit;}
<div class="main">
<div class="maincolumn">
<nav>
<a href="">
<div class="navbox">
Nav 1
</div>
</a>
<a href="">
<div class="navbox">
Nav 2
</div>
</a>
</nav>
</div>
<div class="maincolumn">
<div class="container">
<h2>Titre</h2>
<p>This is a text.</p>
</div>
</div>
</div>
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Flex items are only direct children of a flex container.
Flex items respect order z-index
, but you are z-index
not applying to flex items, but to their descendants.
From the w3c flexbox spec :
Flex elements are colored just like inline CSS21 blocks , except that the
order
-described document order is used instead of the raw document order andz-index
values ββother thanauto
create a stacking context even if .position
static
So, for this you should apply a higher z-index
flex to your first flex item. Demo video:
.main {
font-family: 'Open Sans', Helvetica, sans-serif;
display: flex;
background-color: #99baef;
}
.maincolumn:first-child {
z-index: 1;
}
nav {
height: 100%;
width: 8em;
background-color: black;
}
.navbox {
box-sizing: border-box;
background-color: black;
color: white;
height: 4em;
width: 100%;
text-align: center;
line-height: 4em;
border-top: 1px dotted #99baef;
transition: all 1s;
}
.navbox:hover {
width: 130%;
border-top: none;
background-color: #4a77c4;
color: black;
}
.container {
padding: 1em;
}
a {text-decoration: inherit;}
<div class="main">
<div class="maincolumn">
<nav>
<a href="">
<div class="navbox">
Nav 1
</div>
</a>
<a href="">
<div class="navbox">
Nav 2
</div>
</a>
</nav>
</div>
<div class="maincolumn">
<div class="container">
<h2>Title</h2>
<p>This is a text.</p>
</div>
</div>
</div>
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