<div class="container">

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

  <div class="actions">
    <button id="play">Play</button>
    <button id="reset">Reset</button>
  </div>
</div>
@import url("https://fonts.googleapis.com/css?family=Gochi+Hand");

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  width: 100vw;
  min-height: 100vh;
  margin: 0;
  background-color: #291642;
  font-family: "Gochi Hand", sans-serif;
  font-size: 100%;
  letter-spacing: 0.1rem;
  color: #fff;
  display: flex;
  justify-content: center;
  align-items: center;

  background: linear-gradient(to right, #44ea76 0%, #39fad7 80%, #39fad7 100%)
      no-repeat,
    url("https://s3-us-west-2.amazonaws.com/s.cdpn.io/142996/slider-2.jpg")
      no-repeat fixed;
  background-size: cover;
  background-blend-mode: hue;
}

.container {
  inline-size: 30vw;
  border-radius: 5px;
  margin: 0 1vh;
  box-shadow: 0 20px 30px rgba(0, 0, 0, 0.6);

  text-shadow: 0 1px 1px rgba(0, 0, 0, 0.4);
  transition: box-shadow 0.3s ease;

  background-image: linear-gradient(
    to bottom,
    rgba(146, 135, 187, 0.8) 0%,
    rgba(0, 0, 0, 0.6) 100%
  );
  backdrop-filter: blur(3px);

  min-block-size: 50vh;

  display: flex;
  flex-direction: column;
  align-items: center;

  color: #212121;
  padding: 4vh 2vh;
}

.box {
  width: 20vh;
  height: 20vh;
  background-color: #2196f3;
  border-radius: 100%;
  cursor: pointer;

  margin: auto;
}

button {
  display: inline-flex;
  align-items: center;
  font-size: 1.2rem;
  height: 3rem;
  padding: 0.2rem 3.2rem;
  color: rgba(255, 255, 255, 0.8);
  background: #ff3366;
  border-radius: 10rem;
  border: none;
  cursor: pointer;
  margin-top: 4vh;
}
View Compiled
const aniElement = document.querySelector(".box");
const play = document.getElementById("play");
const reset = document.getElementById("reset");

play.addEventListener("click", () => {
  aniElement.animate(
    {
      transform: ["scale(1, 1)", "scale(1.5, 1.5)"]
    },
    {
      duration: 2000,
      fill: "both"
    }
  );
});

reset.addEventListener("click", () => {
  aniElement.animate(
    {
      transform: ["scale(1.5, 1.5)", "scale(1, 1)"]
    },
    {
      duration: 2000,
      fill: "both"
    }
  );
});

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.