transition-duration CSS property

transition-duration: 500ms;
transition-property: margin-right;

transition-duration: 2s;
transition-property: background-color;

transition-duration: 2s;
transition-property: margin-right, color;

transition-duration: 3s, 1s;
transition-property: margin-right, color;

<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%;
}

/* <time> values */
transition-duration: 6s;
transition-duration: 120ms;
transition-duration: 1s, 15s;
transition-duration: 10s, 30s, 230ms;

/* Global values */
transition-duration: inherit;
transition-duration: initial;
transition-duration: revert;
transition-duration: revert-layer;
transition-duration: unset;

<div class="box duration-1">0.5 seconds</div>

<div class="box duration-2">2 seconds</div>

<div class="box duration-3">4 seconds</div>

<button id="change">Change</button>

.box {
  margin: 20px;
  padding: 10px;
  display: inline-block;
  width: 100px;
  height: 100px;
  background-color: red;
  font-size: 18px;
  transition-property: background-color, font-size, transform, color;
  transition-timing-function: ease-in-out;
}

.transformed-state {
  transform: rotate(270deg);
  background-color: blue;
  color: yellow;
  font-size: 12px;
  transition-property: background-color, font-size, transform, color;
  transition-timing-function: ease-in-out;
}

.duration-1 {
  transition-duration: 0.5s;
}

.duration-2 {
  transition-duration: 2s;
}

.duration-3 {
  transition-duration: 4s;
}

function change() {
  const elements = document.querySelectorAll("div.box");
  for (const element of elements) {
    element.classList.toggle("transformed-state");
  }
}

const changeButton = document.querySelector("#change");
changeButton.addEventListener("click", change);