How to fix stacking/z-index of buttons during animation?

Question

I have side-by-side buttons that are shaped like arrows. In order to achieve this, I am using the ::before and ::after pseudoelements to create rotated squares. They look great, until I try to animate a button. The problem is that the tip of the arrow to the right (::after) must overlap the white square creating the negative/white space behind the next arrow's left edge. I do that by making the ::after square z-index:1, and it works fine. But, when I try to apply a transform to the button in an animation, it breaks the stacking context of the ::before and ::after pseudo elements.

I created a fiddle to demonstrate: https://jsfiddle.net/twnrov23/

<button type="button" class="btn btn-info btn-arrow-right" >1. Step 1</button>
<button type="button" id="button2" class="btn btn-info btn-arrow-right" >2. Step 2</button>
<button type="button" class="btn btn-info btn-arrow-right" >3. Step 3</button>

/* ANIMATION */
.wiggle{
    animation: wiggle 2s linear 1;
}
@keyframes wiggle {
    0%, 7% {
        transform: rotateZ(0);

    }

    15% {
        transform: rotateZ(-15deg);

    }

    20% {
        transform: rotateZ(10deg);

    }

    25% {
        transform: rotateZ(-10deg);

    }

    30% {
        transform: rotateZ(6deg);

    }

    35% {
        transform: rotateZ(-4deg);

    }

    40%, 100% {
        transform: rotateZ(0);

    }
}
/* ARROW BUTTONS */

.btn {
    line-height: 1.25;
}
.btn-arrow-right,
.btn-arrow-left {
    position: relative;
    padding-left: 18px;
    padding-right: 18px;
}

.btn-arrow-right {
    padding-left: 36px;
}

.btn-arrow-left {
    padding-right: 36px;
}

    .btn-arrow-right::before,
    .btn-arrow-right::after,
    .btn-arrow-left::before,
    .btn-arrow-left::after { /* make two squares (before and after), looking similar to the button */
        display: inline-block;
        content: "";
        position: absolute;
        top: 5px; /* move it down because of rounded corners */
        width: 22px; /* same as height */
        height: 22px; /* button_outer_height / sqrt(2) */
        background: inherit; /* use parent background */
        border: inherit; /* use parent border */
        border-left-color: transparent; /* hide left border */
        border-bottom-color: transparent; /* hide bottom border */
        border-radius: 0px 4px 0px 0px; /* round arrow corner, the shorthand property doesn't accept "inherit" so it is set to 4px */
        -webkit-border-radius: 0px 4px 0px 0px;
        -moz-border-radius: 0px 4px 0px 0px;
    }

.btn-arrow-right::before,
.btn-arrow-right::after {
    transform: rotate(45deg); /* rotate right arrow squares 45 deg to point right */
    -webkit-transform: rotate(45deg);
    -moz-transform: rotate(45deg);
    -o-transform: rotate(45deg);
    -ms-transform: rotate(45deg);
}

.btn-arrow-left::before,
.btn-arrow-left::after {
    transform: rotate(225deg); /* rotate left arrow squares 225 deg to point left */
    -webkit-transform: rotate(225deg);
    -moz-transform: rotate(225deg);
    -o-transform: rotate(225deg);
    -ms-transform: rotate(225deg);
}

.btn-arrow-right::before,
.btn-arrow-left::before { /* align the "before" square to the left */
    left: -11px;
}

.btn-arrow-right::after,
.btn-arrow-left::after { /* align the "after" square to the right */
    right: -11px;
}

.btn-arrow-right::after,
.btn-arrow-left::before { /* bring arrow pointers to front */
    z-index: 1;
}

.btn-arrow-right::before,
.btn-arrow-left::after { /* hide arrow tails background */
    background-color: white;
}

When the wiggle class is applied to #button2, the z-index of the ::before and ::after elements is broken.

EDIT 1: If I apply a z-index to each button, where button 1 has z-index 3, button 2 has z-index 2, and button 3 has z-index 1, then it works. Obviously that isn't a great solution because it will require inline css.

do it differently, example: https://stackoverflow.com/a/46755381/8620333 — Temani Afif, Jul 20 '19 at 19:32

Kosh · Answer 1 · 2019-07-21T14:46:50.033

0

Add this to your css:

.btn:nth-of-type(1) {z-index:3}
.btn:nth-of-type(2) {z-index:2}

So it works as expected: https://jsfiddle.net/kx5btzqn/

Another option would be to reverse the order of the buttons in HTML and change direction property: https://jsfiddle.net/9ukrmsvc
So you don't have to set z-index for each button.

edited Jul 21 '19 at 14:46

answered Jul 20 '19 at 19:48

Kosh

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I could put that in css for the max number of buttons I think I would ever have. So that is an improvement. – RJE Jul 20 '19 at 20:33
@RJE, another option would be to reverse the order of the buttons in HTML and change `direction` property: https://jsfiddle.net/9ukrmsvc/ So you don't have to set `z-index` for each button. – Kosh Jul 21 '19 at 14:44

How to fix stacking/z-index of buttons during animation?

1 Answers1