3D-like hover effect on button

Question

I'm trying to replicate this effect with pure CSS:

So far I've tried doing:

.parent {
    height: 90vh;
    width: 100%;

    display: flex;
    align-items: center;
    justify-content: center;
}

.hoverable-element {
        border: 0.1rem solid #000;
        background: #fff;
        padding: 1rem 2rem;

        transform: translate(0, 0);
        box-shadow: 0 0 0 #000;
        
        transition: 
            box-shadow 200ms ease-out,
            transform 200ms ease-out;
}

.hoverable-element:hover {
        transform: translate(-0.5rem, -0.5rem);
        box-shadow: 
            0.1rem 0.1rem 0 #000,
            0.2rem 0.2rem 0 #000,
            0.3rem 0.3rem 0 #000,
            0.4rem 0.4rem 0 #000,
            0.5rem 0.5rem 0 #000;  
}

<div class="parent">
    <button class="hoverable-element">Hoverable Button</button>
</div>

But this method repeats a lot of unnecessary code, as well as not properly doing what I intended. I want the button "shadow" or hover-effect-thingy to be bordered with a white background (as shown in the image). Other than that I'm clueless as to where to start

Answer 1

here is an idea with pseudo element and skew transformation:

.parent {
  height: 90vh;
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hoverable-element {
  border: 1px solid #000;
  background: #fff;
  padding: 1rem 2rem;
  position: relative;
  transition: transform 0.5s;
}

.hoverable-element::before,
.hoverable-element::after {
  content: "";
  position: absolute;
  border: inherit;
  transition: inherit;
}

.hoverable-element::before {
  height: 1rem;
  top: 100%;
  left: -1px;
  right: -1px;
  transform-origin: top left;
  transform: skewX(45deg) scaleY(var(--s, 0));
}

.hoverable-element::after {
  width: 1rem;
  left: 100%;
  top: -1px;
  bottom: 0;
  border-bottom:none;
  transform-origin: bottom left;
  transform: skewY(45deg) scaleX(var(--s, 0));
}

.hoverable-element:hover {
  transform: translate(-0.5rem, -0.5rem);
  --s: 1;
}

<div class="parent">
  <button class="hoverable-element">Hoverable Button</button>
</div>