anchors + transitions

anchors-transitions.markdown

anchors + transitions

A Pen by Stan Williams on CodePen.

License.

index.html

<nav>
  <ul>
    <li><a href="#">Home</a></li>
    <li><a href="#">About</a></li>
    <li><a href="#">Blog</a></li>
    <li><a href="#">Contact</a></li>
  </ul>
</nav>

style.css

html {
  interpolate-size: allow-keywords;
}

body {
  background-image: url("https://images.unsplash.com/photo-1751220170218-e57d53bd4aa8?crop=entropy&cs=tinysrgb&fit=max&fm=jpg&ixid=M3wzMjM4NDZ8MHwxfHJhbmRvbXx8fHx8fHx8fDE3NTE1NjQ0MjR8&ixlib=rb-4.1.0&q=80&w=1800");
  background-attachment: fixed;
}

nav {
  width: fit-content;
  margin: 3rem auto;

  padding: 8px;
  /*   background: black; */
  border-radius: 8px;

  @supports (corner-shape: squircle) {
    border-radius: 24px;
    border-shape: squircle;
  }

  ul:has(:not(:hover)) {
    anchor-name: --test;
  }

  &::before {
    z-index: -2;
    background-attachment: fixed;
    background-image: url("https://images.unsplash.com/photo-1751220170218-e57d53bd4aa8?crop=entropy&cs=tinysrgb&fit=max&fm=jpg&ixid=M3wzMjM4NDZ8MHwxfHJhbmRvbXx8fHx8fHx8fDE3NTE1NjQ0MjR8&ixlib=rb-4.1.0&q=80&w=1800");
  }

  &::after {
    backdrop-filter: blur(2px);
    background-color: hsl(200 100% 100% / 0.1);
    z-index: -1;
  }

  & > ul {
    position: relative;

    &::after {
      content: "";
      position: absolute;
      z-index: -3;
      inset: -8px;
      border-radius: 8px;

      @supports (corner-shape: squircle) {
        border-radius: 24px;
        border-shape: squircle;
      }
      background: hsl(0 0% 0% / 0.8);
      backdrop-filter: blur(2px);
    }
  }

  &::before,
  &::after {
    content: "";
    border-radius: 8px;

    position-anchor: --test;
    position: absolute;
    top: calc(anchor(bottom) - 4px);
    left: calc(anchor(left) + 1rem);
    right: calc(anchor(right) + 1rem);
    bottom: anchor(bottom);

    transition: 500ms;
    transition-timing-function: linear(
      0,
      0.008 1.1%,
      0.031 2.2%,
      0.129 4.8%,
      0.257 7.2%,
      0.671 14.2%,
      0.789 16.5%,
      0.881 18.6%,
      0.957 20.7%,
      1.019 22.9%,
      1.063 25.1%,
      1.094 27.4%,
      1.114 30.7%,
      1.112 34.5%,
      1.018 49.9%,
      0.99 59.1%,
      1
    );
  }

  &:has(a:hover)::before,
  &:has(a:hover)::after {
    @supports (corner-shape: squircle) {
      corner-shape: squircle;
      border-radius: 50%;
    }
    top: anchor(top);
    left: anchor(left);
    right: anchor(right);
  }

  &:has(li:first-of-type a:hover)::before,
  &:has(li:first-of-type a:hover)::after {
    @supports (corner-shape: squircle) {
      border-radius: 32px 50% 50% 32px;
    }
  }

  &:has(li:last-of-type a:hover)::before,
  &:has(li:last-of-type a:hover)::after {
    @supports (corner-shape: squircle) {
      border-radius: 50% 32px 32px 50%;
    }
  }

  > ul {
    padding: 0;
    margin: 0;
    list-style: none;
    display: flex;
  }

  a {
    display: block;
    padding: 1rem;
    text-decoration: none;
    color: white;

    &:hover {
      position: relative;
      display: block;
      anchor-name: --test;
    }
  }
}

html {
  color-scheme: dark;
}

body {
  font-family: system-ui;
  font-size: 2rem;
}