Rotate 45-degree element around vertical axis - css

Question

I've got a series of elements, as shown in the image below:
They are rotated 45 degrees to one side (the content inside -45 degrees, to remain upright).
Now I'd like to rotate each element around a vertical axis, going through the element's center. RotateY doesn't work, as it is at a 45-degree angle.
How would you go about doing this?

Answer 1

The trick is to set this rotation before the 45 degrees rotation:
Notice also that to make the rotation behave really as expect, you need to set it to 0 in the base state
.container {
width: 200px;
height: 200px;
margin: 100px;
border: solid 1px;
transform: rotateY(0deg) rotate(45deg); /* needs Y at 0 deg to behave properly*/
transition: transform 2s;
}
.container:hover {
transform: rotateY(180deg) rotate(45deg); /* notice the order */
}
.inner {
margin: 50px;
transform: rotate(-45deg);
}
<div class="container">
<div class="inner">INNER</div>
</div>

Answer 2

This is how I interpret the question. I'm not very happy with the demo since it needs a lot of structure.
But maybe you can verify the behavior?
Basically I use a wrapper to rotate on the y-axis.
It is key to set the transform origin to the center.
The additional wrapper is used to prevent a flickering on mouse hover.
https://jsfiddle.net/nm59mqky/1/
.tile {
transform: rotateY(0);
transform-origin: center center;
}
.wrapper:hover .tile {
transform: rotateY(180deg);
}

Answer 3

I dont know exactly what your code looks like, but for a simple spinning tile (div) i would try something like this:
#keyframes rotate-vertical {
0% {
transform: rotate3d(0, 1, 0, 0deg);
}
100% {
transform: rotate3d(0, 1, 0, 360deg);
}
}
body {
padding: 20px;
}
.tile {
width: 65px;
height: 65px;
background-color: red;
text-align: center;
transform: rotate3d(0, 0, 1, 45deg);
display: inline-block;
}
.turndiv {
width: 65px;
}
.turndiv:hover {
animation: rotate-vertical 1.1s ease-out;
}
<div class="turndiv">
<div class="tile">
</div>
</div>
You could just do it with transform: rotate3d(); and without a parent div, but to keep it easy i did it like this.