CSS animation-fill-mode and z-index issue - css

Question

I'm using CSS animations (from animate.css) in a project I'm working on.
What I found out is that when fading in a container with an absolutely positioned and z-indexed child in it, the z-index of the child isn't working as it should.
I recreated the issue in this fiddle:
http://jsfiddle.net/Lxsf9ako/
The issue seems to be caused by
animation-fill-mode: both;
This style is placed on the container by animate.css, thus I have no control over this. I could overwrite it by using animation-fill-mode: none, but I rather don't do this for every animation.
Any ideas on this one?
Update:
I just found out this is webkit related, IE11 renders this correctly.
Update 2:
I can't edit the .container class on hover.
Update 3:
The 'hover' in the Fiddle is just a demo. In fact, the .over object is the popup from the angular-ui-bootstrap datepicker directive, and the .container elements are generic elements used throughout the application. Giving them an extra id/class to identify them as datepicker containers is not a clean solution for me.

Answer 1

Just add
#hoverme{
z-index: 1;
}
DEMO
Why you have to do this
Without any z-index value, elements stack in the order that they
appear in the DOM (the lowest one down at the same hierarchy level
appears on top). Elements with non-static positioning will always
appear on top of elements with default static positioning.
Also note that nesting plays a big role. If an element B sits on top
of element A, a child element of element A can never be higher than
element B.
From css-tricks.com
#hoverme {
z-index: 1;
}
.container {
background: rgb(255, 255, 255);
/* Old browsers */
background: -webkit-gradient(linear, 0 0, 0 100%, from(#fff), to(#efefef));
background: -webkit-linear-gradient(#fff 0%, #efefef 100%);
background: -moz-linear-gradient(#fff 0%, #efefef 100%);
background: -o-linear-gradient(#fff 0%, #efefef 100%);
background: linear-gradient(#fff 0%, #efefef 100%);
filter: progid: DXImageTransform.Microsoft.gradient(startColorstr='#ffffff', endColorstr='#efefef', GradientType=0);
/* IE6-9 */
font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
display: block;
width: 100%;
border: 1px solid #c7c7c7;
margin-bottom: 10px;
position: relative;
padding: 20px;
box-sizing: border-box;
-webkit-animation-name: fadeIn;
/* Safari, Chrome and Opera > 12.1 */
-moz-animation-name: fadeIn;
/* Firefox < 16 */
-ms-animation-name: fadeIn;
/* Internet Explorer */
-o-animation-name: fadeIn;
/* Opera < 12.1 */
animation-name: fadeIn;
-webkit-animation-duration: 1s;
-moz-animation-duration: 1s;
-ms-animation-duration: 1s;
-o-animation-duration: 1s;
animation-duration: 1s;
-webkit-animation-fill-mode: both;
-moz-animation-fill-mode: both;
-ms-animation-fill-mode: both;
-o-animation-fill-mode: both;
animation-fill-mode: both;
}
#hoverme .over {
display: none;
padding: 20px;
position: absolute;
top: 20px;
left: 20px;
width: 200px;
background: #efefef;
z-index: 10;
box-sizing: border-box;
-webkit-box-shadow: 2px 2px 4px 0px rgba(0, 0, 0, 0.75);
-moz-box-shadow: 2px 2px 4px 0px rgba(0, 0, 0, 0.75);
box-shadow: 2px 2px 4px 0px rgba(0, 0, 0, 0.75);
}
#hoverme:hover .over {
display: block;
}
#keyframes fadeIn {
0% {
opacity: 0;
}
100% {
opacity: 1;
}
}
/* Firefox < 16 */
#-moz-keyframes fadeIn {
0% {
opacity: 0;
}
100% {
opacity: 1;
}
}
/* Safari, Chrome and Opera > 12.1 */
#-webkit-keyframes fadeIn {
0% {
opacity: 0;
}
100% {
opacity: 1;
}
}
/* Internet Explorer */
#-ms-keyframes fadeIn {
0% {
opacity: 0;
}
100% {
opacity: 1;
}
}
/* Opera < 12.1 */
#-o-keyframes fadeIn {
0% {
opacity: 0;
}
100% {
opacity: 1;
}
}
<div id="hoverme" class="container">
<div class="over">I should be over the next container</div>
</div>
<div class="container">I should be under the .over</div>
Update
You could also use a transition on the .over with opacity and visibility.
#hoverme .over {
opacity: 0;
visibility:hidden;
transition:visibility 0.4s, opacity 0.4s;
...
}
#hoverme:hover .over {
visibility:visible;
opacity:1;
}
DEMO
.container {
background: rgb(255, 255, 255);
/* Old browsers */
background: -webkit-gradient(linear, 0 0, 0 100%, from(#fff), to(#efefef));
background: -webkit-linear-gradient(#fff 0%, #efefef 100%);
background: -moz-linear-gradient(#fff 0%, #efefef 100%);
background: -o-linear-gradient(#fff 0%, #efefef 100%);
background: linear-gradient(#fff 0%, #efefef 100%);
filter: progid: DXImageTransform.Microsoft.gradient(startColorstr='#ffffff', endColorstr='#efefef', GradientType=0);
/* IE6-9 */
font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
display: block;
width: 100%;
border: 1px solid #c7c7c7;
margin-bottom: 10px;
position: relative;
padding: 20px;
box-sizing: border-box;
}
#hoverme .over {
opacity: 0;
visibility: hidden;
transition: visibility 0.4s, opacity 0.4s;
padding: 20px;
position: absolute;
top: 20px;
left: 20px;
width: 200px;
background: #efefef;
z-index: 10;
box-sizing: border-box;
-webkit-box-shadow: 2px 2px 4px 0px rgba(0, 0, 0, 0.75);
-moz-box-shadow: 2px 2px 4px 0px rgba(0, 0, 0, 0.75);
box-shadow: 2px 2px 4px 0px rgba(0, 0, 0, 0.75);
}
#hoverme:hover .over {
visibility: visible;
opacity: 1;
}
<div id="hoverme" class="container">
<div class="over">I should be over the next container</div>
</div>
<div class="container">I should be under the .over</div>

Answer 2

You could change the z-index of the container on hover. Try this:
.container:hover {
z-index:100;
}
Check this http://jsfiddle.net/Lxsf9ako/2/