index.css

.app {
  transition: width, height, margin-top, cubic-bezier(0.25, 1, 0.5, 1) 100ms;
}

.app:hover {
  width: 90px;
  height: 90px;
  margin-top: -30px;
}

/* Right side */
.app:hover + .app {
  width: calc(80px + var(--dock-offset-right, 0px));
  height: calc(80px + var(--dock-offset-right, 0px));
  margin-top: calc(-20px + var(--dock-offset-right, 0px) * -1);
}

.app:hover + .app + .app {
  width: calc(70px + var(--dock-offset-right, 0px));
  height: calc(70px + var(--dock-offset-right, 0px));
  margin-top: calc(-10px + var(--dock-offset-right, 0px) * -1);
}

/* Left side */
.app:has(+ .app:hover){
  width: calc(80px + var(--dock-offset-left, 0px));
  height: calc(80px + var(--dock-offset-left, 0px));
  margin-top: calc(-20px + var(--dock-offset-left, 0px) * -1);
}

.app:has(+ .app + .app:hover){
  width: calc(70px + var(--dock-offset-left, 0px));
  height: calc(70px + var(--dock-offset-left, 0px));
  margin-top: calc(-10px + var(--dock-offset-left, 0px) * -1);
}

/**
 Styling that has nothing to do with the animation:
*/
:root {
  font-family: Inter, system-ui, Avenir, Helvetica, Arial, sans-serif;
  line-height: 1.5;
  font-weight: 400;

  color-scheme: light dark;
  color: rgba(255, 255, 255, 0.87);
  background-color: #242424;

  font-synthesis: none;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  -webkit-text-size-adjust: 100%;
  background-image: url("https://www.frontend.fyi/playground-assets/macos-dock/macos-wallpaper-by-mohammad-alizade-4wzRuAb-KWs-unsplash.webp");
  background-repeat: no-repeat;
  background-size: cover;
}

body{
  margin: 0;
}

.page {
  min-height: 100dvh;
  display: flex;
}

.dock {
  margin: auto auto 12px auto;
  border-radius: 24px;
  padding: 0 12px;
  background-image: linear-gradient(to bottom, rgba(255,255,255,0), rgba(255,255,255,0.15));
  box-shadow:rgba(255, 255, 255, 0.17) 0px 0px 0px 1px inset;
}

.dock ul {
  display: flex;
  list-style-type: none;
  padding: 0;
}

.app {
  width: 60px;
  height: 60px;
  position: relative;
  /* The only reason this padding is disabled, is because the icons have
  a padding in the image that would take too much effort to remove :)
  In case you add custom icons or anything without the padding in the image, you need
  to add this padding on each app element. If you'd add it as a margin between the elements,
  you would lose the over state when moving between icons. */
  /* padding: 0 6px; */
}

.app img {
  width: 100%;
  height: 100%;
}

.app a {
  width: 100%;
  height: 100%;
  display: block;
  border-radius: 12px;
  color: #fff;
}

.app:hover .tooltip,
.app:focus-within .tooltip {
  opacity: 1;
}

.tooltip {
  position: absolute;
  top: -40px;
  left: 50%;
  transform: translateX(-50%);
  opacity: 0;
  transition: ease-in opacity 100ms;
  display: block;
  background: rgba(0,0,0,0.58);
  padding: 8px;
  border-radius: 12px;
  height: 22px;
  width: auto;
  box-shadow:rgba(0, 0, 0, 0.17) 0px 12px 8px 1px;
  white-space: nowrap;
}

.source-links {
  position: absolute;
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  right: 20px;
  top: 20px;
  text-align: right;
}

.source-links a {
  color: #fff;
  opacity: 0.3;
  margin-bottom: 8px;
}

.source-links a:hover {
  opacity: 1;
}

.mobile-message {
  position: absolute;
  width: 100%;
  height: 100%;
  color: #fff;
  font-size: 18px;
  font-weight: 600;
  line-height: 1.2;
  justify-content: center;
  align-items: center;
  display: none;
}

@media only screen and (max-width: 800px) {
  .mobile-message {
    display: flex;
  }
}

.mobile-message p {
  max-width: 70vw;
}

.mobile-message a {
  color: #fff;
}

.mobile-message::before {
  content: "";
  position: fixed;
  inset: 0;
  background-color: rgba(255,255,255,0.3);
  filter: blur(80px);
  -webkit-filter: blur(80px);
}