CSS Transitions

#example-element {
  background-color: #e4f0f5;
  color: black;
  padding: 1rem;
  border-radius: 0.5rem;
  font: 1em monospace;
  width: 100%;
  transition: margin-right 2s;
}

#default-example:hover > #example-element {
  background-color: #990099;
  color: white;
  margin-right: 40%;
}

<section id="default-example">
  <div id="example-element">Hover to see<br />the transition.</div>
</section>

html {
  font-family: "Helvetica", "Arial", sans-serif;
}

[popover] {
  font-size: 1.2rem;
  padding: 10px;
}

[popover]:popover-open {
  opacity: 1;
  transform: scaleX(1);
}

[popover] {
  /* Final state of the exit animation */
  opacity: 0;
  transform: scaleX(0);

  transition-property: opacity, transform, overlay, display;
  transition-duration: 0.7s;
  transition-behavior: allow-discrete;
  /* Using the shorthand transition property, we could write:
    transition: 
      opacity 0.7s,
      transform 0.7s,
      overlay 0.7s allow-discrete,
      display 0.7s allow-discrete;

    or even:
    transition: all 0.7s allow-discrete;
  */
}

/* Needs to be included after the previous [popover]:popover-open 
   rule to take effect, as the specificity is the same */
@starting-style {
  [popover]:popover-open {
    opacity: 0;
    transform: scaleX(0);
  }
}

<button popovertarget="mypopover">Show the popover</button>
<div popover="auto" id="mypopover">I'm a Popover! I should animate.</div>

#example-element {
  background-color: #e4f0f5;
  color: black;
  padding: 1rem;
  border-radius: 0.5rem;
  font: 1em monospace;
  width: 100%;
  transition: margin-right 2s;
}

#default-example:hover > #example-element {
  background-color: #990099;
  color: white;
  margin-right: 40%;
}

<section id="default-example">
  <div id="example-element">Hover to see<br />the transition.</div>
</section>

#example-element {
  background-color: #e4f0f5;
  color: black;
  padding: 1rem;
  border-radius: 0.5rem;
  font: 1em monospace;
  width: 100%;
  transition: margin-right 2s;
}

#default-example:hover > #example-element {
  background-color: #990099;
  color: white;
  margin-right: 40%;
}

<section id="default-example">
  <div id="example-element">Hover to see<br />the transition.</div>
</section>

#example-element {
  background-color: #e4f0f5;
  color: black;
  padding: 1rem;
  border-radius: 0.5rem;
  font: 1em monospace;
  width: 100%;
  transition: margin-right 2s;
}

#default-example:hover > #example-element {
  background-color: #990099;
  color: white;
  margin-right: 40%;
}

<section id="default-example">
  <div id="example-element">Hover to see<br />the transition.</div>
</section>

#example-element {
  background-color: #e4f0f5;
  color: black;
  padding: 1rem;
  border-radius: 0.5rem;
  font: 1em monospace;
  width: 100%;
  transition: margin-right 2s;
}

#default-example:hover > #example-element {
  background-color: #990099;
  color: white;
  margin-right: 40%;
}

<section id="default-example">
  <div id="example-element">Hover to see<br />the transition.</div>
</section>

div {
  width: 200px;
  height: 100px;
  border: 1px solid black;
  margin-top: 10px;
}

div::after {
  content: "class: " attr(class);
  position: relative;
  top: 3px;
  left: 3px;
}

div {
  background-color: yellow;
  transition: background-color 3s;
}

div.showing {
  background-color: skyblue;
}

@starting-style {
  div.showing {
    background-color: red;
  }
}

<button>Display <code>&lt;div&gt;</code></button>

const btn = document.querySelector("button");

btn.addEventListener("click", () => {
  btn.disabled = true;
  const divElem = document.createElement("div");
  divElem.classList.add("showing");
  document.body.append(divElem);

  setTimeout(() => {
    divElem.classList.remove("showing");

    setTimeout(() => {
      divElem.remove();
      btn.disabled = false;
    }, 3000);
  }, 3000);
});