Corner-Shape

by Sebastian Kay

HTML

<div class="container">
  <div class="box"></div>
</div>

CSS

body {
  background: #22c1c3;
  background: linear-gradient(
    0deg,
    rgba(34, 193, 195, 1) 0%,
    rgba(253, 187, 45, 1) 100%
  );
  background-size: 100vw 100vh;
  background-repeat: no-repeat;
  padding: 0;
  margin: 0;
}

.container {
  width: min(900px, 80vw);
  height: 100vh;
  margin: 0 auto 0 auto;
  display: flex;
  justify-content: center;
  align-items: center;

  .box {
    width: 300px;
    height: 300px;
    background: white;
    border-radius: 1rem;
    anchor-name: --box;
    transition: 200ms;

    &:hover {
      corner-top-right-shape: scoop;
      border-top-right-radius: 3em;
    }
  }

  .box::before {
    scale: 0;
    content: 'đź‘Ť';
    position: absolute;
    position-anchor: --box;
    position-area: top right;
    translate: -50% 50%;
    background: #6c4cff;
    color: white;
    font-size: 2rem;
    line-height: 2rem;
    font-weight: bold;
    height: 2em;
    width: 2em;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: 200ms;
  }

  .box:hover::before {
    scale: 1;
  }

  .box::after {
    content: '';
    height: 3em;
    width: 3em;
    background: transparent;
    position: absolute;
    position-anchor: --box;
    top: anchor(top);
    right: anchor(right);
  }
}