Z-index of ::before changing on hover?

Question

I am creating a simple CSS Button and having issues with its z-index.

My Code:

body { /* Ignore Body Styling */
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

button {
  padding: 0.7em 1em;
  font-size: 25px;
  text-transform: uppercase;
  font-weight: 600;
  border: 5px solid #191919;
  border-radius: 0;
  background-color: rebeccapurple;
  color: #fff;
  position: relative;
}

button:hover {
  cursor: pointer;
  transform: translate(-10px, -10px);
}

button::before {
  content: "";
  position: absolute;
  top: 10px;
  left: 10px;
  width: 100%;
  height: 100%;
  z-index: -1;
  background-color: rgb(147, 103, 190);
}

button:hover::before {
  transform: translate(15px, 15px);
  z-index: -1;
}

<button>Click Me</button>

Just run the code once and you will understand.

While :hover, I don't want the ::before to cover over my main element (<button>)

Thank You!

read until the end of the duplicate to get the solution – Temani Afif Sep 26 '21 at 08:09 — Temani Afif, Sep 26 '21 at 08:09

A Haworth · Accepted Answer · 2021-09-26T07:16:26.927

Transforming an element alters the stacking context.

Instead of a translate you could move the element with negative margins.

UPDATE: and compensate for this (so that the following content doesn't move) by adding margin to right and bottom on hover while taking it away at the top and left.

body {
  /* Ignore Body Styling */
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

button {
  padding: 0.7em 1em;
  font-size: 25px;
  text-transform: uppercase;
  font-weight: 600;
  border: 5px solid #191919;
  border-radius: 0;
  background-color: rebeccapurple;
  color: #fff;
  position: relative;
}

button:hover {
  cursor: pointer;
  margin-top: -10px;
  margin-left: -10px;
  margin-bottom: 10px;
  margin-right: 10px;
}

button::before {
  content: "";
  position: absolute;
  top: 10px;
  left: 10px;
  width: 100%;
  height: 100%;
  z-index: -1;
  background-color: rgb(147, 103, 190);
}

button:hover::before {
  transform: translate(15px, 15px);
  z-index: -1;
}

<button>Click Me</button>

That's a good idea, the problem is I have content below the button, so when I change the margin, the whole page just moves. I decided to go with the `transform` because it doesn't change the flow of the page. Do you have any idea how can I set the `z-index` to remain as it was before `:hover`? — Adarsh Dubey, Sep 26 '21 at 06:59
Yes, sorry I should have compensated for that. I have edited the snippet. However, this is all just a pragmatic workaround, it doesn't get to the bottom of the z-index phenomenon and I admit I am lost as to what to do with your original code given the transform creates a new stacking context. — A Haworth, Sep 26 '21 at 07:19

score 2 · Answer 2 · answered Sep 26 '21 at 06:52

Just to suggest an alternative approach, you could play with box shadows to create the effect without creating a pseudo-element.

body {
  height: 80vh;
  display: grid;
  place-items: center;
}

button {
  font-size: 1rem;
  transition: all 0.2s;
  color: white;
  padding: 0.5em 1em;
  text-transform: uppercase;
  background-color: rebeccapurple;
  border: 3px solid black;
  position: relative;
  box-shadow: 5px 5px 0px 0px orchid;
  -webkit-box-shadow: 5px 5px 0px 0px orchid;
  -moz-box-shadow: 5px 5px 0px 0px orchid;
}

button:hover {
  cursor: pointer;
  transform: translate(-5px, -5px);
  box-shadow: 12px 12px 0px 0px orchid;
  -webkit-box-shadow: 12px 12px 0px 0px orchid;
  -moz-box-shadow: 12px 12px 0px 0px orchid;
}

<button>Click Me</button>

That's a nice approach. Though, now as I got stuck with the stacking issue, I really wanna dig in. Do you have any idea how can I set the `z-index` to remain as it was before `:hover`? — Adarsh Dubey, Sep 26 '21 at 07:02
I was also going through the same thing. Came across this https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Positioning/Understanding_z_index/The_stacking_context — Servesh Chaturvedi, Sep 26 '21 at 07:05

score -1 · Answer 3 · answered Sep 26 '21 at 06:43

code issues top: 2px; left: 2px;

<style>
body { /* Ignore Body Styling */
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

button {
  padding: 0.7em 1em;
  font-size: 25px;
  text-transform: uppercase;
  font-weight: 600;
  border: 5px solid #191919;
  border-radius: 0;
  background-color: rebeccapurple;
  color: #fff;
  position: relative;
}

button:hover {
  cursor: pointer;
  transform: translate(-10px, -10px);
}

button::before {
  content: "";
  position: absolute;
  top: 2px;
  left: 2px;
  width: 100%;
  height: 100%;
  z-index: -1;
   background-color: rgb(147, 103, 190);
}
</style>
<button>Click Me</button>

That's not what I want. If you would see the previous answer which was accomplished by negative margins, that's the effect I want. Sorry for not clarifying much — Adarsh Dubey, Sep 26 '21 at 06:56

Z-index of ::before changing on hover?

3 Answers3