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HTML 

              
                <!-- This is the actual demo code. -->
<section class="container basic-layout with-borders">
  <div class="glows">
    <div class="core-cloud"></div>
  </div>
</section>

<!-- This isn't part of the demo - just some controls! -->
<fieldset class="presentation-settings">
  <div class="presentation-settings--container">
    <legend>Toolbox 🧰</legend>
    <div class="presentation-settings--item">
      <input type="checkbox" id="completed-layout" name="completed-layout" data-trigger-class="basic-layout" />
      <label for="completed-layout">Show assembled layout pieces</label>
    </div>
    <div class="presentation-settings--item">
      <input type="checkbox" id="image-borders" name="image-borders" data-trigger-class="with-borders" checked />
      <label for="image-borders">Show image borders</label>
    </div>
  </div>
</fieldset>
!

CSS 

              
                :root {
  --item-size: clamp(30vw, 5em, 100vw);

  background: radial-gradient(#2c2f3e, #0a0f1c);
  overflow: hidden;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica,
    Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
  font-size: 1rem;
  color: #efefef;
}

.container {
  display: flex;
  height: 100vh;
  align-items: center;
  justify-content: center;
}

.glows {
  position: relative;
}

/* These are the glowing rays (before and after) */
.glows::before,
.glows::after {
  border: 2px solid transparent;
  border-radius: 6px;
  transition: border 180ms ease-out;
}

.glows::before {
  content: "";
  position: absolute;
  z-index: 2;
  bottom: 220px;
  left: -130px;
  display: block;
  width: 405px;
  height: 397px;
  background-image: url("https://www.jpmarqu.es/assets/training/light-beam-0@2x.png");
  background-size: 405px 397px;
}
.glows::after {
  content: "";
  position: absolute;
  z-index: 2;
  bottom: 200px;
  left: -100px;
  display: block;
  width: 415px;
  height: 531px;
  background-image: url("https://www.jpmarqu.es/assets/training/light-beam-1@2x.png");
  background-size: 415px 531px;
}

/* This is the glowing center */
.core-cloud {
  display: block;
  width: 496px;
  height: 496px;
  background-image: url("https://www.jpmarqu.es/assets/training/glow-core@2x.png");
  background-size: 496px 496px;
  background-repeat: no-repeat;
  border: 2px solid transparent;
  border-radius: 6px;
  transition: border 180ms ease-out;
}

/* Simulate the layout without our mise-en-place */
.container.basic-layout {
  .glows {
    display: flex;
    gap: 20px;
  }

  .glows::before,
  .glows::after,
  .glows .core-cloud {
    position: relative;
    top: 0;
    left: 0;
    width: var(--item-size);
    height: var(--item-size);
    background-size: var(--item-size);
  }
}

/* Show borders on images */
.container.with-borders {
  .glows::before,
  .glows::after,
  .glows .core-cloud {
    border: 2px solid rgb(255, 255, 255, 0.4);
  }
}

/* -- Demo styles end here -- */
/* Checkbox controls styling */
.presentation-settings {
  z-index: 100;
  position: fixed;
  display: flex;
  align-items: center;
  padding: 15px;
  gap: 6px;
  bottom: 10px;
  left: 10px;
  width: calc(100vw - 50px);
  max-width: 280px;
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.2);
  box-shadow: inset 0 1px 4px 2px rgba(255, 255, 255, 0.033),
    inset 0 6px 10px 3px rgba(255, 255, 255, 0.025);
  backdrop-filter: blur(8px) saturate(150%);
  transform: translate3d(0, 0, 1px);
}

.presentation-settings--container {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.presentation-settings legend {
  font-weight: bold;
  margin-bottom: 6px;
}

.presentation-settings--item {
  display: flex;
  gap: 4px;
  align-items: center;
}
!

JS 

              
                /* This JS only controls the checkbox - the animation we're doing doesn't require any JS ;-) */
const animContainer = document.querySelector(".container");
const checkboxes = document.querySelectorAll(
  '.presentation-settings input[type="checkbox"]'
);

checkboxes.forEach((checkbox) => {
  checkbox.addEventListener("click", (e) => {
    animContainer.classList.toggle(e.target.dataset.triggerClass);
  });
})
!
999px

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